Timing improvements for wireless communications systems

ABSTRACT

Non-terrestrial networks (NTNs) may establish uplink (UL) and downlink (DL) radio frame timing structures to efficiently account for propagation delay and propagation delay variation associated with communications in the NTN. NTNs may manage (synchronize) radio frame timing structures of base stations (e.g., satellites) and user equipment (UEs) in the NTN. Further, UEs may determine timing advance (TA) values to be applied to UL transmissions based on their respective scheduling offset (e.g., offset in UL and DL radio frame timing structures), as well as based on propagation delay or round trip time (RTT). As such, served UEs may determine UL timing such that UL transmissions from the UEs to a satellite arrives at the satellite in a time synchronized manner. In other cases, a satellite may determine UL timing, based on reception timing, such that various UEs in the NTN may implement uniform UL and DL radio frame timing structures.

CROSS REFERENCE

The present Application for Patent claims the benefit of U.S.Provisional Patent Application No. 63/003,687 by RICO ALVARINO et al.,entitled “TIMING IMPROVEMENTS FOR WIRELESS COMMUNICATIONS SYSTEMS,”filed Apr. 1, 2020, assigned to the assignee hereof, and expresslyincorporated by reference herein.

INTRODUCTION

The following relates generally to wireless communications and morespecifically to timing aspects for wireless communications systems.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform spread orthogonal frequency division multiplexing(DFT-S-OFDM). A wireless multiple-access communications system mayinclude one or more base stations or one or more network access nodes,each simultaneously supporting communication for multiple communicationdevices, which may be otherwise known as user equipment (UE).

In some cases, there may be a large distance between a UE and a servingnode of the UE, such as when a gateway or base station and the UE are apart of a non-terrestrial network (NTN). Because of the distance betweenUEs and gateways in such cases, there may be a relatively longround-trip delay or propagation delay in message transmissions between aUE and gateway (e.g., relative to terrestrial networks). Efficienttechniques for managing communications with such relatively longround-trip or propagation delays may thus be desirable for such systems.

SUMMARY

A method of wireless communication at a UE is described. The method mayinclude receiving, from a base station, an indication of a schedulingoffset between a downlink (DL) radio frame timing structure and anuplink (UL) radio frame timing structure, and transmitting an UL messageto the base station based on a timing advance (TA), the TA based on thereceived indication of the scheduling offset.

An apparatus for wireless communication at a UE is described. Theapparatus may include a processor, and memory coupled to the processor.The processor and memory may be configured to receive, from a basestation, an indication of a scheduling offset between a DL radio frametiming structure and an UL radio frame timing structure, and transmit anUL message to the base station based on a TA, the TA based on thereceived indication of the scheduling offset.

Another apparatus for wireless communication at a UE is described. Theapparatus may include means for receiving, from a base station, anindication of a scheduling offset between a DL radio frame timingstructure and an UL radio frame timing structure, and transmitting an ULmessage to the base station based on a TA, the TA based on the receivedindication of the scheduling offset.

A non-transitory computer-readable medium storing code for wirelesscommunication at a UE is described. The code may include instructionsexecutable by a processor to receive, from a base station, an indicationof a scheduling offset between a DL radio frame timing structure and anUL radio frame timing structure, and transmit an UL message to the basestation based on a TA, the TA based on the received indication of thescheduling offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a range ofTA values based on the scheduling offset, where the TA may be determinedbased on the range. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining anorbit type associated with the base station, where the range may bedetermined based on the orbit type.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a TAthreshold, where the TA may be determined based on the TA threshold. Insome examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the TA threshold may bedetermined based on one or more of a slot duration, a radio framenumerology, and a buffering capability of the UE. Some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein may further include operations, features, means, orinstructions for receiving an indication of a common offset associatedwith a cell served by the base station, where the TA may be determinedbased on the common offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a range ofTA values based on the common offset, where the TA may be determinedbased on the range. In some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein, the TA may bebased on a round trip time (RTT) for communications with the basestation. In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the RTT for communicationswith the base station may be determined based on one or more of aposition of the UE, a position of the base station, a distance betweenthe UE and the base station, a timestamp corresponding to a DL messagereceived from the base station, and a local timestamp.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a networkoffset between a network DL radio frame timing structure and a networkUL radio frame timing structure, where the TA may be determined based onthe network offset. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining arange of TA values based on the network offset, where the TA may bedetermined based on the range. Some examples of the method, apparatuses,and non-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for receiving anindication of the network offset, where the network offset may bedetermined based on the indication of the network offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a minimumoffset between the DL radio frame timing structure and the UL radioframe timing structure, where the TA may be determined based on theminimum offset. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining aninitial TA based on the minimum offset, and transmitting a physicalrandom access channel (PRACH) message based on the initial TA. In someexamples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the scheduling offset isbased on an NTN.

A method of wireless communication at a base station is described. Themethod may include transmitting, to the UE, an indication of ascheduling offset between a DL radio frame timing structure and an ULradio frame timing structure, and receiving an UL message from the UEbased on a range of TA values, the range of TA values based on thescheduling offset.

An apparatus for wireless communication at a base station is described.The apparatus may include a processor and memory coupled to theprocessor. The processor and memory may be configured to transmit, tothe UE, an indication of a scheduling offset between a DL radio frametiming structure and an UL radio frame timing structure, and receive anUL message from the UE based on a range of TA values, the range of TAvalues based on the scheduling offset.

Another apparatus for wireless communication at a base station isdescribed. The apparatus may include means for transmitting, to the UE,an indication of a scheduling offset between a DL radio frame timingstructure and an UL radio frame timing structure, and receiving an ULmessage from the UE based on a range of TA values, the range of TAvalues based on the scheduling offset.

A non-transitory computer-readable medium storing code for wirelesscommunication at a base station is described. The code may includeinstructions executable by a processor to transmit, to the UE, anindication of a scheduling offset between a DL radio frame timingstructure and an UL radio frame timing structure, and receive an ULmessage from the UE based on a range of TA values, the range of TAvalues based on the scheduling offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining the rangeof TA values based on the scheduling offset, where the UL message may bereceived from the UE based on the range. Some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein may further include operations, features, means, or instructionsfor determining an orbit type associated with the base station, wherethe range may be determined based on the orbit type.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a TAthreshold, where a TA may be determined based on the TA threshold. Insome examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the TA threshold may bedetermined based on one or more of a slot duration, a radio framenumerology, and a buffering capability of the UE. Some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein may further include operations, features, means, orinstructions for determining a common offset associated with a cellserved by the base station, and transmitting an indication of the commonoffset to the UE, where the UL message may be received from the UE basedon the common offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a networkoffset between a network DL radio frame timing structure and a networkUL radio frame timing structure, where the UL message may be receivedfrom the UE based on the network offset. Some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein may further include operations, features, means, or instructionsfor transmitting an indication of the network offset to the UE.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a minimumoffset between the DL radio frame timing structure and the UL radioframe timing structure, where a TA may be determined based on theminimum offset. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining aninitial TA based on the minimum offset, and receiving a PRACH messagefrom the UE based on the initial TA. In some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein, the scheduling offset is based on an NTN.

A method of wireless communication at a UE is described. The method mayinclude receiving, from a base station, a random access response messageincluding a fractional TA, and transmitting, to the base station inresponse to the random access response message, a second random accessmessage including a differential offset between a first slot boundaryassociated with a base station radio frame timing structure and a secondslot boundary associated with a UE radio frame timing structure.

An apparatus for wireless communication at a UE is described. Theapparatus may include a processor and memory coupled to the processor.The processor and memory may be configured to receive, from a basestation, a random access response message including a fractional TA, andtransmit, to the base station in response to the random access responsemessage, a second random access message including a differential offsetbetween a first slot boundary associated with a base station radio frametiming structure and a second slot boundary associated with a UE radioframe timing structure.

Another apparatus for wireless communication at a UE is described. Theapparatus may include means for receiving, from a base station, a randomaccess response message including a fractional TA, and transmitting, tothe base station in response to the random access response message, asecond random access message including a differential offset between afirst slot boundary associated with a base station radio frame timingstructure and a second slot boundary associated with a UE radio frametiming structure.

A non-transitory computer-readable medium storing code for wirelesscommunication at a UE is described. The code may include instructionsexecutable by a processor to receive, from a base station, a randomaccess response message including a fractional TA, and transmit, to thebase station in response to the random access response message, a secondrandom access message including a differential offset between a firstslot boundary associated with a base station radio frame timingstructure and a second slot boundary associated with a UE radio frametiming structure.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a RTT forcommunications with a base station, and transmitting a first randomaccess message to the base station based on the RTT, where the randomaccess response message may be received based on transmitting the firstrandom access message. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining ascrambling sequence, a hopping pattern, or both based on the RTT.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a TA basedon the differential offset, and transmitting an UL message to the basestation based on the TA. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for receiving, fromthe base station, an indication to shift the UE radio frame timingstructure, and shifting the UE radio frame timing structure based on theindication, where the TA may be determined based on the shifting. Insome examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the differential offset maybe determined based on the fractional TA. In some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein, the base station is associated with an NTN.

A method of wireless communication at a UE is described. The method mayinclude receiving, from a base station, an indication of a schedulingoffset between a UL radio frame timing structure and an UL radio frametiming structure, determining an RTT for communications with the basestation, determining a TA based on the scheduling offset and the RTT,and transmitting an UL message to the base station based on the TA.

An apparatus for wireless communication at a UE is described. Theapparatus may include a processor, memory coupled with the processor,and instructions stored in the memory. The instructions may beexecutable by the processor to cause the apparatus to receive, from abase station, an indication of a scheduling offset between a UL radioframe timing structure and an UL radio frame timing structure, determinean RTT for communications with the base station, determine a TA based onthe scheduling offset and the RTT, and transmit an UL message to thebase station based on the TA.

Another apparatus for wireless communication at a UE is described. Theapparatus may include means for receiving, from a base station, anindication of a scheduling offset between a UL radio frame timingstructure and an UL radio frame timing structure, determining an RTT forcommunications with the base station, determining a TA based on thescheduling offset and the RTT, and transmitting an UL message to thebase station based on the TA.

A non-transitory computer-readable medium storing code for wirelesscommunication at a UE is described. The code may include instructionsexecutable by a processor to receive, from a base station, an indicationof a scheduling offset between a UL radio frame timing structure and anUL radio frame timing structure, determine an RTT for communicationswith the base station, determine a TA based on the scheduling offset andthe RTT, and transmit an UL message to the base station based on the TA.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a range ofTA values based on the scheduling offset, where the TA may be determinedbased on the range. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining anorbit type associated with the base station, where the range may bedetermined based on the orbit type.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a TAthreshold, where the TA may be determined based on the TA threshold. Insome examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the TA threshold may bedetermined based on one or more of a slot duration, a radio framenumerology, and a buffering capability of the UE. Some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein may further include operations, features, means, orinstructions for receiving an indication of a common offset associatedwith a cell served by the base station, where the TA may be determinedbased on the common offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a range ofTA values based on the common offset, where the TA may be determinedbased on the range. In some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein, the RTT forcommunications with the base station may be determined based on one ormore of a position of the UE, a position of the base station, a distancebetween the UE and the base station, a timestamp corresponding to a ULmessage received from the base station, and a local timestamp.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a networkoffset between a network UL radio frame timing structure and a networkUL radio frame timing structure, where the TA may be determined based onthe network offset. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining arange of TA values based on the network offset, where the TA may bedetermined based on the range. Some examples of the method, apparatuses,and non-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for receiving anindication of the network offset, where the network offset may bedetermined based on the indication of the network offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a minimumoffset between the UL radio frame timing structure and the UL radioframe timing structure, where the TA may be determined based on theminimum offset. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining aninitial TA based on the minimum offset, and transmitting a PRACH messagebased on the initial TA. In some examples of the method, apparatuses,and non-transitory computer-readable medium described herein, thescheduling offset is based on an NTN.

A method of wireless communication at a base station is described. Themethod may include determining a minimum RTT for communications with aUE, transmitting, to the UE, an indication of a scheduling offsetbetween a UL radio frame timing structure and an UL radio frame timingstructure, and receiving an UL message from the UE based on thescheduling offset.

An apparatus for wireless communication at a base station is described.The apparatus may include a processor, memory coupled with theprocessor, and instructions stored in the memory. The instructions maybe executable by the processor to cause the apparatus to determine aminimum RTT for communications with a UE, transmit, to the UE, anindication of a scheduling offset between a UL radio frame timingstructure and an UL radio frame timing structure, and receive an ULmessage from the UE based on the scheduling offset.

Another apparatus for wireless communication at a base station isdescribed. The apparatus may include means for determining a minimum RTTfor communications with a UE, transmitting, to the UE, an indication ofa scheduling offset between a UL radio frame timing structure and an ULradio frame timing structure, and receiving an UL message from the UEbased on the scheduling offset.

A non-transitory computer-readable medium storing code for wirelesscommunication at a base station is described. The code may includeinstructions executable by a processor to determine a minimum RTT forcommunications with a UE, transmit, to the UE, an indication of ascheduling offset between a UL radio frame timing structure and an ULradio frame timing structure, and receive an UL message from the UEbased on the scheduling offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a range ofTA values based on the scheduling offset, where the UL message may bereceived from the UE based on the range. Some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein may further include operations, features, means, or instructionsfor determining an orbit type associated with the base station, wherethe range may be determined based on the orbit type.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a TAthreshold, where the TA may be determined based on the TA threshold. Insome examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the TA threshold may bedetermined based on one or more of a slot duration, a radio framenumerology, and a buffering capability of the UE. Some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein may further include operations, features, means, orinstructions for determining a common offset associated with a cellserved by the base station, and transmitting an indication of the commonoffset to the UE, where the UL message may be received from the UE basedon the common offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a networkoffset between a network UL radio frame timing structure and a networkUL radio frame timing structure, where the UL message may be receivedfrom the UE based on the network offset. Some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein may further include operations, features, means, or instructionsfor transmitting an indication of the network offset to the UE.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a minimumoffset between the UL radio frame timing structure and the UL radioframe timing structure, where the TA may be determined based on theminimum offset. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining aninitial TA based on the minimum offset, and receiving a PRACH messagefrom the UE based on the initial TA. In some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein, the scheduling offset is based on an NTN.

A method of wireless communication at a UE is described. The method mayinclude receiving, from a base station, a random access response messageincluding a fractional TA, determining, a differential offset between afirst slot boundary associated with a base station radio frame timingstructure and a second slot boundary associated with a UE radio frametiming structure, and transmitting, to the base station in response tothe random access response message, a second random access messageincluding the differential offset.

An apparatus for wireless communication at a UE is described. Theapparatus may include a processor, memory coupled with the processor,and instructions stored in the memory. The instructions may beexecutable by the processor to cause the apparatus to receive, from abase station, a random access response message including a fractionalTA, determine, a differential offset between a first slot boundaryassociated with a base station radio frame timing structure and a secondslot boundary associated with a UE radio frame timing structure, andtransmit, to the base station in response to the random access responsemessage, a second random access message including the differentialoffset.

Another apparatus for wireless communication at a UE is described. Theapparatus may include means for receiving, from a base station, a randomaccess response message including a fractional TA, determining, adifferential offset between a first slot boundary associated with a basestation radio frame timing structure and a second slot boundaryassociated with a UE radio frame timing structure, and transmitting, tothe base station in response to the random access response message, asecond random access message including the differential offset.

A non-transitory computer-readable medium storing code for wirelesscommunication at a UE is described. The code may include instructionsexecutable by a processor to receive, from a base station, a randomaccess response message including a fractional TA, determine, adifferential offset between a first slot boundary associated with a basestation radio frame timing structure and a second slot boundaryassociated with a UE radio frame timing structure, and transmit, to thebase station in response to the random access response message, a secondrandom access message including the differential offset.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a RTT forcommunications with a base station, and transmitting a first randomaccess message to the base station based on the RTT, where the randomaccess response message may be received based on transmitting the firstrandom access message. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for determining ascrambling sequence, a hopping pattern, or both based on the RTT.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a TA basedon the differential offset, and transmitting an UL message to the basestation based on the TA. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for receiving, fromthe base station, an indication to shift the UE radio frame timingstructure, and shifting the UE radio frame timing structure based on theindication, where the TA may be determined based on the shifting. Insome examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the differential offset maybe determined based on the fractional TA. In some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein, the base station is associated with an NTN.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communicationsthat supports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system thatsupports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure.

FIGS. 3A and 3B illustrate examples of frame timing diagrams thatsupport timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure.

FIG. 4 illustrates example timing diagrams that support timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure.

FIG. 5 illustrates an example of a frame timing diagram that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure.

FIG. 6 illustrates an example of a frame timing diagram that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure.

FIG. 7 illustrates an example of a frame timing diagram that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure.

FIG. 8 illustrates an example of a process flow that supports timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure.

FIG. 9 illustrates an example of a process flow that supports timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure.

FIGS. 10 through 27 show flowcharts illustrating methods that supporttiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure.

DETAILED DESCRIPTION

NTNs may provide coverage by using high-altitude vehicles between userterminals and gateways or base stations (e.g., next-generation NodeBs orgiga-NodeBs (which may be referred to as a gNB, and also referred to asaccess stations or access gateways)). A gateway may, for example,transmit data to a satellite which may then be relayed to a userterminal or vice-versa. A high-altitude vehicle itself may be a basestation, in some examples. A user terminal may be any device capable oftransmitting signals to a satellite. Examples of a user terminal mayinclude a UE, a relay equipment configured to relay a signal between asatellite and a user terminal, or a combination thereof. NTNs mayinvolve the use of high altitude platform stations (HAPSs) and/orsatellites to provide coverage for terrestrial base stations and UEs.The terms HAPS and satellite may be used interchangeably herein to referto a remote NTN device that may provide coverage to one or more otherhigh altitude or terrestrial devices. Likewise, the terms gateway andbase station may be used interchangeably herein to refer to a networknode that serves a UE and provides network access to the UE. In somecases, the base station (e.g., gNB) may be itself on the satellite, orthe functionality of the base station may be split between the satelliteand the gateway (e.g., the satellite may be a distributed unit (DU) andthe gateway a central unit (CU), or other architectures). One or moreaspects of the techniques described herein may be applicable inscenarios where the gNB is on the gateway, the satellite, or split amonggateway and satellite.

The gateway and the satellite may be thousands of kilometers apart andit may take some time for electromagnetic waves to propagate over thedistance between the gateway and the satellite and between the satelliteand the user terminal. Thus, the propagation delay for NTNs may be manyorders of magnitude larger than the propagation delay for terrestrialnetworks. As such, the round trip delay (RTD), or sometimes referred toas an RTT) associated with a signal may also be orders of magnitudelarger for NTNs than for terrestrial networks. Further, due to the highmobility of high-altitude vehicles such as non-geostationary satellites,communications with the non-geostationary satellites may promote largeand time-varying RTDs. These variations in RTD may affect user terminalsto experience variation in UL timing and frequency synchronization withsatellites. As demand for communication efficiency increases, it may bedesirable for wireless communications systems to support a techniquesfor estimating and determining UL timing (e.g., including DL and ULradio frame timing structures, UL transmission timing, etc.) thataccounts for RTD as well as variation in RTD.

According to the techniques described herein, a satellite and/or servedUEs may account for UE-specific propagation delay and propagation delayvariation between UEs and the satellite such that UL transmissions maybe either synchronized at the UEs (e.g., synchronized with a nearestslot boundary) or synchronized at the satellite and/or gateway (e.g.,synchronized at the network). For example, an NTN may establish (e.g.,via preconfigured network specification, via signaling, such as systeminformation block (SIB) signaling, etc.) UL and DL radio frame timingstructures to efficiently account for propagation delay and propagationdelay variation associated with communications in the NTN. For instance,UL and DL radio frame timing structures at the UE and at the satellitemay be offset to account for propagation delay and propagation delayvariation. As described herein, a scheduling offset (K_(offset)) betweena UE's UL and DL radio frame timing structure may be based on a worstcase RTT within the NTN (K_(offset)=RTT_(Worstcase)) or a differencebetween the worst case RTT and the best case RTT within the NTN(K_(offset)=RTT_(WorstCase)−RTT_(BestCase)).

In examples where, UL transmissions are synchronized at the UEs (e.g.,synchronized with a nearest slot boundary), K_(offset)=0 and the networkmay account for different UE offsets at the network based on thepropagation delay variation between UEs. In such examples, thetechniques described herein may provide for improved random accesschannel (RACH) procedures (e.g., to account for UEs following their owntiming when the satellite is unaware of UE location before RACHprocedures). For instance, a UE may include a differential offset (e.g.,between a first slot boundary associated with a satellite radio frametiming structure and a second slot boundary associated with a UE radioframe timing structure) in a RACH Msg3 to the satellite. In some cases,the satellite may use the differential offset to determine UE timing forsubsequent UL communications. In some cases, the UE may determine thedifferential offset based on a fractional TA value sent to the UE in arandom access response (RAR) during the RACH procedure prior totransmitting the RACH Msg3 including the determined differential offset.

Further, UEs may determine TA values to be applied to UL transmissionsbased on their respective scheduling offset (K_(offset)), as well asbased on propagation delay or RTT. As such, in some cases, served UEsmay determine UL timing such that UL transmissions from the UEs to asatellite arrive at the satellite in a time synchronized manner (e.g.,such that communications from two or more UEs scheduled in a same DLtime slot arrive at a same corresponding UL time slot from theperspective of the satellite). According to various examples describedherein, the UE may apply a TA (e.g., to determine UL timing) that isbased on the UE radio frame timing structure in addition to estimatedpropagation delay (e.g., a UE-specific RTT), propagation delay variationbetween served UEs and the satellite (e.g., differential offset), etc.In some cases, the serving gateway may provide information related toRTD, information related to variation in RTD across UEs of the NTN, orboth, to assist the UE in determining UL timing. In other examples, asatellite (e.g., or a gateway, the network, etc.) may determine ULtiming, based on reception timing, such that UL transmissions from thevarious UEs may be transmitted uniformly (e.g., according to a sameoffset, according to a same radio frame timing structure at the UEs,etc.).

The described techniques may support reliable NTN timing alignment ofcommunications between a base station or satellite and one or more UEsserved by the base station or satellite. For instance, the describedtechniques may provide for reliable (e.g., improved) estimation oftiming offsets, and reliable estimation of TA values for UL, etc.relating to communications between high-altitude vehicles (e.g.,satellites or other non-terrestrial-based equipment), user terminals,and gateways, in NTNs. As such, supported techniques may includefeatures for efficient NTNs and efficient non-terrestrialcommunications. The described techniques may also support increasedspectral efficiency and, in some examples, may promote higher mobilitysupport for user terminals in NTNs compared to terrestrial networks.

Aspects of the disclosure are initially described in the context ofexample wireless communications systems. Aspects of the disclosure arealso illustrated by example frame timing diagrams and example processflow diagrams. Aspects of the disclosure are further illustrated by anddescribed with reference to apparatus diagrams, system diagrams, andflowcharts that relate to timing improvements for wirelesscommunications systems.

FIG. 1 illustrates an example of a wireless communications system 100that supports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure. Thewireless communications system 100 may include one or more base stations105, one or more UEs 115, and a core network 130. In some examples, thewireless communications system 100 may be an NTN, an LTE network, anLTE-A network, an LTE-A Pro network, or a New Radio (NR) network. Insome examples, the wireless communications system 100 may supportenhanced broadband communications, ultra-reliable (e.g., missioncritical) communications, low latency communications, communicationswith low-cost and low-complexity devices, or any combination thereof.

The described techniques relate to improved methods, systems, devices,and apparatuses that support timing improvements for wirelesscommunications systems. Generally, the described techniques provide fortiming relationships amongst devices (e.g., UEs 115 and satellites 120)communicating via an NTN. For example, the techniques described hereinmay be implemented to manage (e.g., synchronize) radio frame timingstructures of base stations 105 (e.g., satellites 120) and UEs 115 in anNTN. Relatively large differences in round-trip delays or propagationdelays associated with communications from various UEs 115 in an NTN mayresult in large offsets between DL and UL frame timing of such UEs 115.According to the techniques described herein, timing enhancements may beemployed by an NTN to account for such large offsets between frametiming of different UEs 115 within the NTN.

Generally, timing may be aligned at either the base station (e.g., thesatellite 120) or at the UEs 115 served by the base station 105 orsatellite 120. In cases where timing is aligned at the base station 105or satellite 120, UEs 115 served by the base station 105 or satellite120 may apply various advances to UL transmissions (e.g., based on UE115 proximity to the satellite 120, RTD corresponding to communicationsassociated with the UE 115, etc.) such that UL transmissions may bealigned at the receiving base station 105 or satellite 120. For example,an NTN (e.g., wireless communications system 100) may establish (e.g.,via preconfigured network specification, via signaling, such as SIBsignaling, etc.) UL and DL radio frame timing structures to efficientlyaccount for propagation delay and propagation delay variation associatedwith communications in the NTN. In cases where timing is aligned at theUEs 115, UEs 115 of an NTN may transmit UL transmissions uniformly(e.g., radio frame timing structures may be uniform across served UEs)and the base station 105 or satellite 120 may account for variations inreception timing (e.g., based on varying differences in RTDscorresponding to communications associated with the served UEs 115).

Further, UEs 115 may determine TA values to be applied to ULtransmissions based on their respective UL and DL radio frame timingstructure, as well as based on propagation delay, propagation delayvariation, etc. As such, in some cases, served UEs 115 may determine ULtiming such that UL transmissions from the UEs 115 to a satellite 120arrive at the satellite 120 in a time synchronized manner (e.g., suchthat communications from two or more UEs 115 scheduled in a same DL timeslot arrive at a same corresponding UL time slot from the perspective ofthe satellite 120). According to various examples, the UE 115 may applya TA, to determine the UL timing, that is based on the UE 115 radioframe timing structure in addition to estimated propagation delay (e.g.,a UE-specific RTT), propagation delay variation between served UEs 115and the satellite 120 (e.g., differential offset), etc. In some cases,the serving gateway (e.g., a base station 105) may provide informationrelated to RTD, information related to variation in RTD across UEs 115of the NTN, or both, to assist the UE 115 in determining UL timing. Inother examples, a satellite 120 (e.g., or a gateway, the network, etc.)may determine UL timing, based on reception timing, such that ULtransmissions from the various UEs 115 may be transmitted uniformly(e.g., according to a same offset, according to a same radio frametiming structure at the UEs 115, etc.).

The base stations 105 may be dispersed throughout a geographic area toform the wireless communications system 100 and may be devices indifferent forms or having different capabilities. The base stations 105and the UEs 115 may wirelessly communicate via one or more communicationlinks 125. Each base station 105 may provide a coverage area 110 overwhich the UEs 115 and the base station 105 may establish one or morecommunication links 125. The coverage area 110 may be an example of ageographic area over which a base station 105 and a UE 115 may supportthe communication of signals according to one or more radio accesstechnologies.

The UEs 115 may be dispersed throughout a coverage area 110 of thewireless communications system 100, and each UE 115 may be stationary,or mobile, or both at different times. The UEs 115 may be devices indifferent forms or having different capabilities. Some example UEs 115are illustrated in FIG. 1. The UEs 115 described herein may be able tocommunicate with various types of devices, such as other UEs 115, thebase stations 105, or network equipment (e.g., core network nodes, relaydevices, integrated access and backhaul (IAB) nodes, or other networkequipment), as shown in FIG. 1.

The base stations 105 may communicate with the core network 130, or withone another, or both. For example, the base stations 105 may interfacewith the core network 130 through one or more backhaul links (e.g., viaan S1, N2, N3, or other interface). The base stations 105 maycommunicate with one another over the backhaul links (e.g., via an X2,Xn, or other interface) either directly (e.g., directly between basestations 105), or indirectly (e.g., via core network 130), or both. Insome examples, the backhaul links may be or include one or more wirelesslinks.

One or more of the base stations 105 described herein may include or maybe referred to by a person having ordinary skill in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or agiga-NodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, awireless device, a remote device, a handheld device, or a subscriberdevice, or some other suitable terminology, where the “device” may alsobe referred to as a unit, a station, a terminal, or a client, amongother examples. A UE 115 may also include or may be referred to as apersonal electronic device such as a cellular phone, a personal digitalassistant (PDA), a tablet computer, a laptop computer, or a personalcomputer. In some examples, a UE 115 may include or be referred to as awireless local loop (WLL) station, an Internet of Things (IoT) device,an Internet of Everything (IoE) device, or a machine type communications(MTC) device, among other examples, which may be implemented in variousobjects such as appliances, or vehicles, meters, among other examples.

The UEs 115 described herein may be able to communicate with varioustypes of devices, such as other UEs 115 that may sometimes act as relaysas well as the base stations 105 and the network equipment includingmacro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations,among other examples, as shown in FIG. 1.

The UEs 115 and the base stations 105 may wirelessly communicate withone another via one or more communication links 125 over one or morecarriers. The term “carrier” may refer to a set of radio frequencyspectrum resources having a defined physical layer structure forsupporting the communication links 125. For example, a carrier used fora communication link 125 may include a portion of a radio frequencyspectrum band (e.g., a bandwidth part (BWP)) that is operated accordingto one or more physical layer channels for a given radio accesstechnology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layerchannel may carry acquisition signaling (e.g., synchronization signals,system information), control signaling that coordinates operation forthe carrier, user data, or other signaling. The wireless communicationssystem 100 may support communication with a UE 115 using carrieraggregation or multi-carrier operation. A UE 115 may be configured withmultiple DL component carriers and one or more UL component carriersaccording to a carrier aggregation configuration. Carrier aggregationmay be used with both frequency division duplexing (FDD) and timedivision duplexing (TDD) component carriers.

Signal waveforms transmitted over a carrier may be made up of multiplesubcarriers (e.g., using multi-carrier modulation (MCM) techniques suchas orthogonal frequency division multiplexing (OFDM) or DFT-S-OFDM). Ina system employing MCM techniques, a resource element may consist of onesymbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing (SCS) areinversely related. The number of bits carried by each resource elementmay depend on the modulation scheme (e.g., the order of the modulationscheme, the coding rate of the modulation scheme, or both). Thus, themore resource elements that a UE 115 receives and the higher the orderof the modulation scheme, the higher the data rate may be for the UE115. A wireless communications resource may refer to a combination of aradio frequency spectrum resource, a time resource, and a spatialresource (e.g., spatial layers or beams), and the use of multiplespatial layers may further increase the data rate or data integrity forcommunications with a UE 115.

The time intervals for the base stations 105 or the UEs 115 may beexpressed in multiples of a basic time unit which may, for example,refer to a sampling period of T_(S)=1/(Δf_(max)·N_(f)) seconds, whereΔf_(max) may represent the maximum supported SCS, and N_(f) mayrepresent the maximum supported discrete Fourier transform (DFT) size.Time intervals of a communications resource may be organized accordingto radio frames each having a specified duration (e.g., 10 milliseconds(ms)). Each radio frame may be identified by a system frame number (SFN)(e.g., ranging from 0 to 1023).

Each frame may include multiple consecutively numbered subframes orslots, and each subframe or slot may have the same duration. In someexamples, a frame may be divided (e.g., in the time domain) intosubframes, and each subframe may be further divided into a number ofslots. Alternatively, each frame may include a variable number of slots,and the number of slots may depend on SCS. Each slot may include anumber of symbol periods (e.g., depending on the length of the cyclicprefix prepended to each symbol period). In some wireless communicationssystems 100, a slot may further be divided into multiple mini-slotscontaining one or more symbols. Excluding the cyclic prefix, each symbolperiod may contain one or more (e.g., N_(f)) sampling periods. Theduration of a symbol period may depend on the SCS or frequency band ofoperation.

A subframe, a slot, a mini-slot, or a symbol may be the smallestscheduling unit (e.g., in the time domain) of the wirelesscommunications system 100 and may be referred to as a transmission timeinterval (TTI). In some examples, the TTI duration (e.g., the number ofsymbol periods in a TTI) may be variable. Additionally or alternatively,the smallest scheduling unit of the wireless communications system 100may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a DL carrier, for example, using one or more of timedivision multiplexing (TDM) techniques, frequency division multiplexing(FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g.,a control resource set (CORESET)) for a physical control channel may bedefined by a number of symbol periods and may extend across the systembandwidth or a subset of the system bandwidth of the carrier. One ormore control regions (e.g., CORESETs) may be configured for a set of theUEs 115. For example, one or more of the UEs 115 may monitor or searchcontrol regions for control information according to one or more searchspace sets, and each search space set may include one or multiplecontrol channel candidates in one or more aggregation levels arranged ina cascaded manner. An aggregation level for a control channel candidatemay refer to a number of control channel resources (e.g., controlchannel elements (CCEs)) associated with encoded information for acontrol information format having a given payload size. Search spacesets may include common search space sets configured for sending controlinformation to multiple UEs 115 and UE-specific search space sets forsending control information to a specific UE 115.

In some examples, a base station 105 may be movable and thereforeprovide communication coverage for a moving geographic coverage area110. In some examples, different geographic coverage areas 110associated with different technologies may overlap, but the differentgeographic coverage areas 110 may be supported by the same base station105. In other examples, the overlapping geographic coverage areas 110associated with different technologies may be supported by differentbase stations 105. The wireless communications system 100 may include,for example, a heterogeneous network in which different types of thebase stations 105 provide coverage for various geographic coverage areas110 using the same or different radio access technologies.

The wireless communications system 100 may be configured to supportultra-reliable communications or low-latency communications, or variouscombinations thereof. For example, the wireless communications system100 may be configured to support ultra-reliable low-latencycommunications (URLLC) or mission critical communications. The UEs 115may be designed to support ultra-reliable, low-latency, or criticalfunctions (e.g., mission critical functions). Ultra-reliablecommunications may include private communication or group communicationand may be supported by one or more mission critical services such asmission critical push-to-talk (MCPTT), mission critical video (MCVideo),or mission critical data (MCData). Support for mission criticalfunctions may include prioritization of services, and mission criticalservices may be used for public safety or general commercialapplications. The terms ultra-reliable, low-latency, mission critical,and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 may also be able to communicate directly withother UEs 115 over a device-to-device (D2D) communication link 135(e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115utilizing D2D communications may be within the geographic coverage area110 of a base station 105. Other UEs 115 in such a group may be outsidethe geographic coverage area 110 of a base station 105 or be otherwiseunable to receive transmissions from a base station 105. In someexamples, groups of the UEs 115 communicating via D2D communications mayutilize a one-to-many (1:M) system in which each UE 115 transmits toevery other UE 115 in the group. In some examples, a base station 105facilitates the scheduling of resources for D2D communications. In othercases, D2D communications are carried out between the UEs 115 withoutthe involvement of a base station 105.

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC) or 5G core (5GC), which may include at leastone control plane entity that manages access and mobility (e.g., amobility management entity (MME), an access and mobility managementfunction (AMF)) and at least one user plane entity that routes packetsor interconnects to external networks (e.g., a serving gateway (S-GW), aPacket Data Network (PDN) gateway (P-GW), or a user plane function(UPF)). The control plane entity may manage non-access stratum (NAS)functions such as mobility, authentication, and bearer management forthe UEs 115 served by the base stations 105 associated with the corenetwork 130. User IP packets may be transferred through the user planeentity, which may provide IP address allocation as well as otherfunctions. The user plane entity may be connected to the networkoperators IP services 150. The operators IP services 150 may includeaccess to the Internet, Intranet(s), an IP Multimedia Subsystem (IMS),or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may includesubcomponents such as an access network entity 140, which may be anexample of an access node controller (ANC). Each access network entity140 may communicate with the UEs 115 through one or more other accessnetwork transmission entities 145, which may be referred to as radioheads, smart radio heads, or transmission/reception points (TRPs). Eachaccess network transmission entity 145 may include one or more antennapanels. In some configurations, various functions of each access networkentity 140 or base station 105 may be distributed across various networkdevices (e.g., radio heads and ANCs) or consolidated into a singlenetwork device (e.g., a base station 105).

The wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band because thewavelengths range from approximately one decimeter to one meter inlength. The UHF waves may be blocked or redirected by buildings andenvironmental features, but the waves may penetrate structuressufficiently for a macro cell to provide service to the UEs 115 locatedindoors. The transmission of UHF waves may be associated with smallerantennas and shorter ranges (e.g., less than 100 kilometers) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz.

The wireless communications system 100 may utilize both licensed andunlicensed radio frequency spectrum bands. For example, the wirelesscommunications system 100 may employ License Assisted Access (LAA),LTE-Unlicensed (LTE-U) radio access technology, or NR technology in anunlicensed band such as the 5 GHz industrial, scientific, and medical(ISM) band. When operating in unlicensed radio frequency spectrum bands,devices such as the base stations 105 and the UEs 115 may employ carriersensing for collision detection and avoidance. In some examples,operations in unlicensed bands may be based on a carrier aggregationconfiguration in conjunction with component carriers operating in alicensed band (e.g., LAA). Operations in unlicensed spectrum may includeDL transmissions, UL transmissions, P2P transmissions, or D2Dtransmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas,which may be used to employ techniques such as transmit diversity,receive diversity, multiple-input multiple-output (MIMO) communications,or beamforming. The antennas of a base station 105 or a UE 115 may belocated within one or more antenna arrays or antenna panels, which maysupport MIMO operations or transmit or receive beamforming. For example,one or more base station antennas or antenna arrays may be co-located atan antenna assembly, such as an antenna tower. In some examples,antennas or antenna arrays associated with a base station 105 may belocated in diverse geographic locations. A base station 105 may have anantenna array with a number of rows and columns of antenna ports thatthe base station 105 may use to support beamforming of communicationswith a UE 115. Likewise, a UE 115 may have one or more antenna arraysthat may support various MIMO or beamforming operations. Additionally oralternatively, an antenna panel may support radio frequency beamformingfor a signal transmitted via an antenna port.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105, a UE 115) to shape or steeran antenna beam (e.g., a transmit beam, a receive beam) along a spatialpath between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that some signals propagatingat particular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying amplitude offsets, phase offsets, or both to signals carriedvia the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

The electromagnetic spectrum is often subdivided, based onfrequency/wavelength, into various classes, bands, channels, etc. In 5GNR two initial operating bands have been identified as frequency rangedesignations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). Itshould be understood that although a portion of FR1 is greater than 6GHz, FR1 is often referred to (interchangeably) as a “Sub-6 GHz” band invarious documents and articles. A similar nomenclature issue sometimesoccurs with regard to FR2, which is often referred to (interchangeably)as a “millimeter wave” band in documents and articles, despite beingdifferent from the extremely high frequency (EHF) band (30 GHz-300 GHz)which is identified by the International Telecommunications Union (ITU)as a “millimeter wave” band.

The frequencies between FR1 and FR2 are often referred to as mid-bandfrequencies. Recent 5G NR studies have identified an operating band forthese mid-band frequencies as frequency range designation FR3 (7.125GHz-24.25 GHz). Frequency bands falling within FR3 may inherit FR1characteristics and/or FR2 characteristics, and thus may effectivelyextend features of FR1 and/or FR2 into mid-band frequencies. Inaddition, higher frequency bands are currently being explored to extend5G NR operation beyond 52.6 GHz. For example, three higher operatingbands have been identified as frequency range designations FR4 a orFR4-1 (52.6 GHz-71 GHz), FR4 (52.6 GHz-114.25 GHz), and FR5 (114.25GHz-300 GHz). Each of these higher frequency bands falls within the EHFband.

With the above aspects in mind, unless specifically stated otherwise, itshould be understood that the term “sub-6 GHz” or the like if usedherein may broadly represent frequencies that may be less than 6 GHz,may be within FR1, or may include mid-band frequencies. Further, unlessspecifically stated otherwise, it should be understood that the term“millimeter wave” or the like if used herein may broadly representfrequencies that may include mid-band frequencies, may be within FR2,FR4, FR4-a or FR4-1, and/or FR5, or may be within the EHF band.

The wireless communications system 100 includes base stations 105, UEs115, satellites 120, and a core network 130. In some examples, thewireless communications system 100 may be an LTE network, an LTE-Anetwork, an LTE-A Pro network, or a NR network. In some cases, wirelesscommunications system 100 may support enhanced broadband communications,ultra-reliable (e.g., mission critical) communications, low latencycommunications, or communications with low-cost and low-complexitydevices.

Wireless communications system 100 may also include one or moresatellites 120. Satellite 120 may communicate with base stations 105(also referred to as gateways in NTNs) and UEs 115 (or other highaltitude or terrestrial communications devices). Satellite 120 may beany suitable type of communication satellite configured to relaycommunications between different end nodes in a wireless communicationsystem. Satellite 120 may be an example of a space satellite, a balloon,a dirigible, an airplane, a drone, an unmanned aerial vehicle, and/orthe like. In some examples, the satellite 120 may be in a geosynchronousor geostationary earth orbit, a low earth orbit (LEO) or a medium earthorbit (MEO). A satellite 120 may be a multi-beam satellite configured toprovide service for multiple service beam coverage areas in a predefinedgeographical service area. The satellite 120 may be any distance awayfrom the surface of the earth.

In some cases, a cell may be provided or established by a satellite 120as part of an NTN. A satellite 120 may, in some cases, perform thefunctions of a base station 105, act as a bent-pipe satellite, or mayact as a regenerative satellite, or a combination thereof. In othercases, satellite 120 may be an example of a smart satellite, or asatellite with intelligence. For example, a smart satellite may beconfigured to perform more functions than a regenerative satellite(e.g., may be configured to perform particular algorithms beyond thoseused in regenerative satellites, to be reprogrammed, etc.). A bent-pipetransponder or satellite may be configured to receive signals fromground stations and transmit those signals to different ground stations.In some cases, a bent-pipe transponder or satellite may amplify signalsor shift from UL frequencies to DL frequencies. A regenerativetransponder or satellite may be configured to relay signals like thebent-pipe transponder or satellite, but may also use on-board processingto perform other functions. Examples of these other functions mayinclude demodulating a received signal, decoding a received signal,re-encoding a signal to be transmitted, or modulating the signal to betransmitted, or a combination thereof. For example, a bent-pipesatellite (e.g., satellite 120) may receive a signal from a base station105 and may relay the signal to a UE 115 or base station 105, orvice-versa.

UEs 115 may communicate with satellites 120 and/or base stations orgateways 105 using communications links 125. In some cases, timingadjustments to account for propagation delay communications links 125via a satellite 120 may include a propagation delay between a UE 115 anda satellite 120, a propagation delay between a base station 105 and asatellite 120, as well as a variation in the propagation delays due tomovement of the satellite. In accordance with various techniquesdiscussed herein, radio frame timing structures for UL and DLcommunications (e.g., offsets between a DL radio frame timing structureand an UL radio frame timing structure of the UE 115, offsets betweensatellite 120 radio frame timing structure and UE 115 radio frame timingstructure, etc.) may provide for efficient communications in NTN (e.g.,via efficient accounting for large propagation delays or RTTs, largevariation in propagation delays or RTTs between different UEs 115 in anNTN, etc.). Further, a UE 115 may account for variation in propagationdelay, in addition to determined propagation delay itself, whendetermining an UL timing for UL communications via a satellite 120.

For example, generally, the described techniques provide for timingrelationships amongst devices (e.g., UEs 115 and satellites 120)communicating via an NTN (e.g., via wireless communications system 100).One or more aspects of the described techniques may be implemented tomanage (e.g., synchronize) radio frame timing structures of basestations 105, satellites 105, and UEs 115 in an NTN, such as in wirelesscommunications system 100. Relatively large differences in round-tripdelays or propagation delays associated with communications from variousUEs 115 in an NTN may result in large offsets between DL and UL frametiming of such UEs 115. According to the techniques described herein,timing enhancements may be employed by an NTN to account for such largeoffsets between frame timing of different UEs 115 within the NTN.

The discussed techniques may be described with reference to satellitetiming, however one or more aspects of such techniques may be applied togateway timing (e.g., base station 105 timing) by analogy withoutdeparting from the scope of the present disclosure. Generally, thedescribed techniques (e.g., radio frame timing structures, radio frametiming structure offsets, UL transmission timing, TA determination, TAapplication, etc.) may be applicable to UE 115 and satellite 120communications, UE 115 and base station 105 communications, base station105 and satellite 120 communications, etc.

NTNs (e.g., such as wireless communications system 100) may establish(e.g., via preconfigured network specification, via signaling, such asSIB signaling, etc.) UL and DL radio frame timing structures toefficiently account for propagation delay and propagation delayvariation associated with communications in the NTN. In cases wheretiming is aligned at the UEs 115 (e.g., when K_(offset)=0), UEs 115 ofthe NTN may transmit UL transmissions uniformly (e.g., each UE 115 mayhave a same offset between DL radio frame timing structure and an ULradio frame timing structure) and the base station 105 or satellite 120may account for variations in reception timing (e.g., based on varyingdifferences in RTDs or RTTs corresponding to communications associatedwith the served UEs 115).

Further, UEs 115 may determine TA values to be applied to ULtransmissions based on their respective scheduling offset (K_(offset)),as well as based on propagation delay or RTT (e.g., which may bedetermined by the UE 115 or indicated via satellite 120 signaling). Assuch, in some cases, served UEs 115 may determine UL timing such that ULtransmissions from the UEs 115 to a satellite 120 arrives at thesatellite 120 in a time synchronized manner (e.g., such thatcommunications from two or more UEs 115 scheduled in a same DL time slotarrive at a same corresponding UL time slot from the perspective of thesatellite 120). According to various examples, UEs 115 may apply a TAand/or determine timing of UL transmissions based on the estimatedpropagation delay (e.g., a UE-specific RTT), propagation delay variationbetween served UEs 115 and the satellite 120 (e.g., differentialoffset), etc. In some cases, the serving gateway may provide informationrelated to RTD, variation in RTD, or both, to assist a UE 115 indetermining UL timing. In other examples, a satellite 120 (e.g., or abase station 105, a gateway, the network, etc.) may determine UL timing,based on reception timing, such that UL transmissions from the variousUEs 115 may be transmitted uniformly (e.g., according to a same offset,according to a same radio frame timing structure at the UE, etc.).

A UE 115 may include a UE communications manager 101 (e.g., which may beexamples of a communications manager 1015 described herein). The UEcommunications manager 101 may receive, from a base station 105 or asatellite 120, an indication of a scheduling offset between a DL radioframe timing structure and an UL radio frame timing structure. The UEcommunications manager 101 may determine an RTT for communications withthe base station 105 or the satellite 120, and the UE communicationsmanager 101 may then determine a TA based on the scheduling offset andthe RTT. The UE communications manager 101 may transmit an UL message tothe base station 105 or the satellite 120 based on the TA.

In some examples, the UE communications manager 101 may receive, from abase station 105 or a satellite 120, a random access response messageincluding a fractional TA and the UE communications manager 101 maydetermine a differential offset between a first slot boundary associatedwith a base station/satellite radio frame timing structure and a secondslot boundary associated with the UE 115 radio frame timing structure.The UE communications manager 101 may transmit, to the base station 105or the satellite 120 in response to the random access response message,a second random access message including the differential offset.

A satellite 120 (e.g., or in some examples a base station 105) mayinclude a satellite communications manager 102 (e.g., which may beexamples of a communications manager 1415 described herein). Thesatellite communications manager 102 may determine a minimum RTT forcommunications with a UE 115. The satellite communications manager 102may transmit, to the UE 115, an indication of a scheduling offsetbetween a DL radio frame timing structure and an UL radio frame timingstructure. The satellite communications manager 102 receive an ULmessage from the UE 115 based on the scheduling offset.

FIG. 2 illustrates an example of a wireless communications system 200that supports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure. In someexamples, wireless communications system 200 may implement aspects ofwireless communications system 100. Wireless communications system 200may include a gateway such as base station 105-a, a UE 115-a, and asatellite 120-a (e.g., which in some cases may also be referred to as abase station 105), which may be examples of a base station 105, UEs 115,and satellites 120 as described with reference to FIG. 1. The gateway105-a may serve a coverage area 110-a in cases of a terrestrial network,and the satellite 120-a may serve coverage area 110-a in cases of anNTN.

In some examples, the satellite 120-a may relay communications betweenthe gateway (e.g., base station 105-a) and the UE 115-a. For example,the gateway or base station 105-a may communicate with the UE 115-a viathe satellite 120-a or vice-versa. In some examples, for communicationsoriginating at the gateway 105-a and going to the UE 115-a, the gateway105-a may transmit an UL transmission 205-a to the satellite 120-a,which in some cases may be referred to as a feeder link. The satellite120-a may relay the UL transmission 205-a as a DL transmission 205-b tothe UE 115-a, which in some cases may be referred to as a service link.In other examples, for communications originating at the UE 115-a andgoing to the gateway 105-a, the UE 115-a may transmit an UL transmission210-a to the satellite 120-a via service link. The satellite 120-a mayrelay the UL transmission 210-a as a DL transmission 210-b to gateway105-b via the feeder link.

The gateway 105-a and the satellite 120-a may be thousands of kilometersapart and it may take some time for electromagnetic waves to propagateover the distance between the gateway 105-a and the satellite 120-a andbetween the satellite 120-a and the UE 115-a. The propagation delay forNTNs may be many orders of magnitude larger than the propagation delayfor terrestrial networks. As such, the RTD (e.g., communication delaydue to RTT associated with signal propagation) associated with atransmission may also be orders of magnitude larger for NTNs than forterrestrial networks. In addition, high speeds of non-geostationarysatellites, for example, such as the satellite 120-a may promotevariation in RTD. As a result, the UE 115-a may experience variation inUL timing synchronization with the satellite 120-a. Likewise, thegateway 105-a may experience variation in UL and DL timingsynchronization with the satellite 120-a. Thus, in some examples, atotal propagation delay may be comprised of a first portion of thepropagation delay and a first propagation delay variation for theUE-to-satellite link, and a second portion of the propagation delay anda second propagation delay variation for the satellite-to-gateway link.In some cases, RTD information includes a satellite-to-gatewaypropagation delay, and where the UE determines a UE-to-satellitepropagation delay for use in an initial access procedure, and where thepropagation delay variation is determined subsequent to the initialaccess procedure.

By way of example, the satellite 120-a may be in an orbit, such as LEO,MEO, or geostationary earth orbit. In any of these examples, thesatellite 120-a may be many thousands of kilometers from earth, andtherefore may be thousands of kilometers from the gateway 105-a and theUE 115-a. Each transmission 205 or 210 between the gateway 105-a and theUE 115-a may therefore travel from earth the distance to the satellite120-a and back to earth. The distance that a transmission travels mayincrease the propagation delay of a transmission or RTD associated withthe transmission. The propagation delay may refer to a duration it takesfor a signal to travel from its source to its intended recipient. TheRTD may refer to a duration (e.g., a RTT) it takes for a transmission tobe transmitted from a source to its intended recipient, processed by theintended recipient, and a response transmitted from the intendedrecipient of the transmission back to the source.

The UE 115-a may support a closed-loop timing control to maintain an ULtiming synchronization (or UL timing accuracy) with the satellite 120-a,or with the gateway 105-a. The UE 115-a, in some examples, may rely onnetwork signaled RTD information or a RTD variation rate (of a beamcenter of the satellite 120-a) when the UE 115-a is unable to determineits geolocation within the geographic coverage area 110-a. When thesatellite 120-a is in a low-earth orbit, the satellite 120-a may bebetween 600 km to 2000 km from earth and travelling at a rate of 7.5km/s. In the example of a LEO location of the satellite 120-a, forexample, such as a 1200 km orbit from earth with an elevation angle of30° the RTD variation rate may be on the order of 35 microseconds (μs)per second (s) (μs/s).

In order to provide synchronized UL and DL timing at the gateway 105-a,communications to and from the gateway 105-a may be made according to agateway 105-a timing reference. In order to provide synchronized UL andDL timing at the satellite 120-a, communications to and from thesatellite 120-a may be made according to a satellite 120-a timingreference. In order to provide synchronized UL and DL timing at the UE115-a, communications to and from the satellite UE 115-a may be madeaccording to a UE 115-a timing reference. In some examples, thedescribed techniques may provide for efficient synchronization of UL andDL timing at the satellite 120-a (e.g., via implementation of ascheduling offset K_(offset)). In other examples, the describedtechniques may provide for efficient synchronization of UL and DL timingat the satellite 120-a (e.g., where K_(offset)=0). Generally, thedescribed techniques may be applied for synchronized UL and DL timing atthe gateway 105-a (e.g., where techniques for UL communications from UE115-a may be applicable to DL communications from satellite 120-a togateway 105-a, by analogy, without departing from the scope of thepresent disclosure).

For instance, in cases where UL and DL timing is synchronized at thegateway 105-a, the UE 115-a may adjust a timing of UL communications tothe gateway 105-a such that the UL communications are transmitted farenough in advance of a timing boundary or frame boundary at the gateway105-a to have a time of arrival at the gateway 105-a that corresponds tothe timing boundary or frame boundary. In other cases, the UE 115-a mayuse a satellite 120-a timing reference for UL communications, to providethat UL communications are received at the satellite 120-a at a desiredtime or frame boundary. In either case, the satellite 120-a may have asufficient propagation delay variation that the UE 115-a UL timing maybe based on the propagation delay and the propagation delay variation.

FIGS. 5 and 6 may illustrate an example of a satellite 120-a timingreference in accordance with various aspects of the disclosure, with theunderstanding that such relative timing references may be applied incases where the gateway 105-a timing reference is used for determinationof UL transmission timing. Further, FIG. 7 may illustrate an example ofa UE 115-a timing reference in accordance with various aspects of thedisclosure, with the understanding that aspects of such techniques maybe applied at a satellite 120-a for reception of UL communication fromUE 115-a or at a gateway 105-a for reception of DL communication fromsatellite 120-a.

Generally, considering UEs with global navigation satellite system(GNSS) and without GNSS, the UE may identify or determine (e.g., eithervia explicit signaling, via network specification or preconfiguration,or via derivation from other parameters) one or more of a minimum offset(M), a scheduling slot offset (S), and a portion of the offset that iscaptured at the network side (P). For implementing radio frame timingstructures analogous to example frame timing diagram 500 (e.g., wheretiming is fully aligned at the network), M=N−D, S=N, and P=0. Forimplementing radio frame timing structures analogous to example frametiming diagram 600 (e.g., where timing is aligned with an offset, suchas with a common offset N−D), M=N−D, S=D, and P=N−D. In some cases, aminimum offset may be implemented for UEs without GNSS for initial TAfor PRACH.

In some cases, relationships between M, S, and P (as well as the TA) maybe limited by wireless communications systems (e.g., by NTNs). Forexample, wireless communications systems (e.g., UEs and radio frametiming structures in an NTN) may adhere to S+P−M<z, where z may bespecified or preconfigured by the network, where z may depend ondeployment, etc. (e.g., which may limit buffering at the UE, forinstance, by limiting the max time between receiving a DL controlinformation (DCI) and transmitting PUSCH). Additionally oralternatively, wireless communications systems (e.g., UEs and radioframe timing structures in an NTN) may adhere to M−P<TA<M−P+y, where ymay be specified or preconfigured by the network, where y may depend ondeployment, etc. (e.g., which may limit the range of TA at the UE).

FIG. 3A and FIG. 3B illustrate example frame timing diagram 300 andexample frame timing diagram 301, respectively, that each support timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure. In some examples, frametiming diagram 300 and/or frame timing diagram 301 may implement aspectsof wireless communications system 100 and/or wireless communicationssystem 200. For example, frame timing diagram 300 and/or frame timingdiagram 301 may be based on a configuration by a gateway 105 (or asatellite 120), and implemented by a UE 115 for estimating anddetermining UL timing (or implemented by a satellite 120 for estimatingand determining DL timing) in an NTN, as described with reference toFIGS. 1 and 2. Generally, FIG. 3A and FIG. 3B may illustrate one or moreaspects that may allow frameworks (e.g., NTNs) to define timingrelationships at a base station (e.g., a gNB, which may refer to agateway and/or a satellite) and a UE.

In the example frame timing diagrams illustrated by FIGS. 3A, 3B, 4, 5,6, and 7, gNB timing may illustrate one or more aspects of a radio frametiming structure for a gateway or satellite. For example, gNB DL 305timing may illustrate one or more aspects of a DL radio frame timingstructure for a gateway or satellite, and gNB UL 320 timing mayillustrate one or more aspects of an UL radio frame timing structure fora gateway or satellite. Further, UE timing may illustrate one or moreaspects of a radio frame timing structure for a UE. For example, UE DL310 timing may illustrate one or more aspects of a DL radio frame timingstructure for a UE, and UE UL 315 timing may illustrate one or moreaspects of an UL radio frame timing structure for a UE. gNB timing andUE timing may be associated with boundaries such as slot boundaries,frame or subframe boundaries, etc. In some cases, gNB timing and UEtiming may have a number of frame boundaries that correspond to slots orSFNs.

FIG. 3A may illustrate a large TA 330 in an NTN that may result in alarge offset in the UEs DL frame timing and UL frame timing. Forinstance, in frame timing diagram 300, gNB DL 305-a timing and gNB UL320-a timing may be aligned (e.g., a gNB DL frame n 340-a may be alignedwith corresponding gNB UL frame n 340-d). UE DL 310-a timing may lag thegNB timing (gNB DL 305-a timing) by an amount of propagation delay 325-abetween the UE and the gNB (e.g., which may include a UE-to-satellitepropagation delay or both a UE-to-satellite propagation delay and asatellite-to-gateway propagation delay). In order to provide ULcommunications that are received at the gNB and synchronized with gNBSFN or slot boundaries, UE UL 315-a timing may have each correspondingSFN or slot advanced ahead of the UE DL 310-a timing by an amount of theTA 330-a (e.g., which may correspond to a RTT or RTD). In other words,UL and DL radio frame timing structures of the UE may be offset suchthat a UE DL frame n 340-b may be shifted compared to UE UL frame n340-c by a TA 330-a. gNB DL frame n 340-d may be delayed by a delay325-b behind UE UL frame n 340-c. As described herein, in some cases,UEs may thus transmit UL communications with very large TAs 330 in NTNs(e.g., TAs 330 to the order of hundreds of milliseconds (ms)).

Alternatively, if a smaller TA 330 is used, gNB DL 305 timing and gNB UL320 timing may not be aligned. For example, FIG. 3B may illustrate areduced TA 330 in an NTN that may result in a large offset in the gNBsDL frame timing and UL frame timing. For instance, in frame timingdiagram 301, gNB DL 305-b timing and gNB UL 320-b timing may be offset(e.g., a gNB DL frame n 340-e may be offset from corresponding gNB ULframe n 320-b by a gNB DL-UL frame timing shift 335). UE DL 310-b timingmay lag the gNB timing (gNB DL 305-b timing) by an amount of propagationdelay 325-c between the UE and the gNB (e.g., which may include aUE-to-satellite propagation delay or both a UE-to-satellite propagationdelay and a satellite-to-gateway propagation delay). In order to provideUL communications that are synchronized with UE SFN or slot boundaries,UE UL 315-b timing may have each corresponding SFN or slot advancedahead of the UE DL 310-b timing by an amount of the TA 330-b (e.g., a UEUL frame n 340-f may be advanced ahead of UE DL frame n 340-g). gNB ULframe n 340-h may be delayed by a delay 325-d behind UE UL frame n340-g.

FIG. 4 illustrates an example of a timing diagram 400 and a timingdiagram 401 that support timing improvements for wireless communicationssystems in accordance with one or more aspects of the presentdisclosure. In some examples, timing diagram 400 and/or timing diagram401 may implement aspects of wireless communications system 100,wireless communications system 200, frame timing diagram 300, and/orframe timing diagram 301. For example, timing diagram 400 and/or timingdiagram 401 may be based on a configuration by a gateway 105 (or asatellite 120), and implemented by a UE 115 for estimating anddetermining UL timing (or implemented by a satellite 120 for estimatingand determining DL timing) in an NTN, as described with reference toFIGS. 1-3. Generally, FIG. 4 may illustrate one or more aspects that mayallow frameworks (e.g., NTNs) to define timing relationships at a basestation (gNB, which may refer to a gateway and/or a satellite) and a UE.

Generally, NTNs may employ one of two high level alternatives. In gNBtime (e.g., from the timing perspective of a satellite, a base station,a gateway, etc.), two UEs scheduled in the same instant (e.g., in thesame DL frame) with a same offset (K) may be received at the same time(e.g., in a same UL frame corresponding to the scheduling DL frame), ortwo UEs scheduled in the same instant (e.g., in the same DL frame) witha same offset (K) may be received at different times (e.g., in differentUL frames due to differences in RTTs between the two UEs scheduled viathe same DL frame). Various aspects of the discussed timing enhancementsmay be described with reference to a scheduling offset (K_(offset)), aworst case RTT (N), a difference between the worst case RTT and the bestcase RTT (D), and an estimated RTT at a UE X (N_(x)). In some cases, theestimated RTT at a UE X (N_(x)) may be referred to as a UE-specific RTT.For example, the estimated RTT at a worst case UE (e.g., which maycorrespond to a UE furthest from the gNB, a UE moving away from the gNB,etc.) would be N_(x)=N, and the estimated RTT at a best case UE (e.g.,where the best case RTT may correspond to a UE closest to the gNB, a UEmoving towards the gNB, etc.) would be N_(x)=N−D.

Example timing diagram 400 may illustrate the first alternativedescribed above where timing is aligned at the gNB (e.g., where a sameRTT is observed by the gNB for a close UE and a far UE). For example, agNB may transmit DCI (e.g., included in physical DL control channel(PDCCH) signaling) at 405-a. The DCI may schedule two UEs (‘Close UE’and ‘Far UE’) for UL transmission (e.g., for physical uplink sharedchannel (PUSCH) signaling, which may be scheduled via an UL grant inDCI). The close UE may receive the DL message at 410-a and the far UEmay receive the DL message at 415-a (e.g., due to differences in RTTassociated with the two UEs). For example, due to proximity with a gNBin an NTN, a close UE and a far UE may have differences in RTTs (e.g.,such as RTTs differing by 10 or more ms) that may be significant (e.g.,relative to radio frame timing at the gNB and UEs).

Both UEs may be scheduled to transmit a corresponding UL message aftersome K1 slots (e.g., where K1 may be some scheduling offset configuredby the network), and the close UE may delay transmission of the ULmessage by an additional duration D such that both UL messages may bereceived at the gNB at the same time (at 430-a). As such, a far UE maytransmit an UL message (e.g., corresponding to the DL message receivedat 415-a) at 420-a, and a close UE may transmit an UL message (e.g.,corresponding to the DL message received at 410-a) at 425-a. Due to thedifferences in RTT for UL transmission by the close UE and the far UE,and due to the additional delay (D) employed by the close UE, ULmessages corresponding to the DL scheduling (transmitted by the gNB at405-a) may be received by the base station at a same time 430-a.

Alternatively, example timing diagram 401 may illustrate the secondalternative described above where timing is aligned at the UEs (e.g.,where a different RTTs are observed by the gNB for a close UE and a farUE). For example, a gNB may transmit DCI (e.g., via PDCCH signaling) at405-b. The DCI may schedule two UEs (‘Close UE’ and ‘Far UE’) for ULtransmission (e.g., for PUSCH signaling, which may be scheduled via anUL grant in DCI). The close UE may receive the DL message at 410-b andthe far UE may receive the DL message at 415-b (e.g., due to differencesin RTT associated with the two UEs). For example, due to proximity witha gNB in an NTN, a close UE and a far UE may have differences in RTTs(e.g., such as RTTs differing by 10 or more ms) that may be significant(e.g., relative to radio frame timing at the gNB and UEs).

Both UEs may be scheduled to transmit a corresponding UL message aftersome K1 slots (e.g., where K1 may be some scheduling offset configuredby the network). As such (e.g., in cases where the close UE does notdelay transmission of the UL message by an additional duration D), theclose UE may transmit an UL message (e.g., corresponding to the DLmessage received at 410-b) at 425-b and the far UE may transmit an ULmessage (e.g., corresponding to the DL message received at 415-b) at420-b. Therefore, due to the differences in RTT for DL reception of ascheduling grant and for UL transmission by the close UE and the far UE,UL messages corresponding to the DL scheduling (transmitted by the gNBat 405-a) may be received by the base station at a different times(e.g., UL corresponding to the scheduled close UE may be received at435-b and UL corresponding to the scheduled far UE may be received at430-b).

As such, techniques described herein may provide for efficient timingstructures (e.g., UL and DL radio frame timing structures at a gNB, aswell as UL and DL radio frame timing structures at a UE) to manage sucheffects of differing RTTs between UEs of a same cell (e.g., betweenclose UE and far UE served by a gNB).

For instance, in cases where timing is aligned at the gNB (e.g., as inexample timing diagram 400), a UE DL timing structure may lag the gNBtiming structure by an amount of propagation delay between the UE andthe gateway (e.g., which may include a UE-to-satellite propagation delayor both a UE-to-satellite propagation delay and a satellite-to-gatewaypropagation delay). In order to provide UL communications that arereceived at the gNB and synchronized with gNB SFN or slot boundaries, UEUL timing may have each corresponding SFN or slot advanced ahead of theUE DL timing by an amount of the RTD, which may take into accountpropagation delay variation due to, for example, UE proximity to thegNB.

In some cases, for initial access the UE may transmit a random accessrequest to the gNB to initiate a connection establishment. In somecases, an initial RTD value for random access requests may be broadcastby the gNB, and may be sufficient for the gNB to receive and decode therandom access request even in the presence of some timing error. The gNBmay transmit a RAR and TA value to the UE in response to the randomaccess request. In some cases, the gNB may also provide informationrelated to propagation delay variation.

In cases where the gNB timing reference is used for determination of ULtiming (e.g., such as for the determination of D or the determination ofthe UL time 425-a), the one way propagation delay may corresponds to thedelay between the UE and the gNB (e.g., which may include delay betweenthe UE and the satellite (UE-satellite delay) or both the UE-satellitedelay plus satellite-gateway delay). In some examples, the UE may beable to estimate the propagation delay, for example in cases where theUE has a GNSS capability. In cases where satellite reference timing isused, the service link may be aligned according to satellite clock, andthe gateway may adjust its transmit timing to compensate delay betweensatellite and gateway, and thus the UE may not need to consider timingvariation of the feeder link due to satellite movement relative togateway.

In cases where the UE uses the gNB timing reference, when the UEreceives UL scheduling (e.g., in DCI of a DL message from the gNB), theUE may determine the UL timing according to the received DL signaltiming plus a TA, plus a scheduling offset (K_(offset)) (e.g., inaddition to the K1 offset and/or K2 offset). In some cases, the gNB orother network node may broadcast information about RTD (e.g., to be usedin initial access such as a random access procedure). In some cases, thegNB may broadcast the RTD between the satellite and the UE. In somecases, the UE may determine RTD between the UE and the satellite, basedon one or more of a GNSS capability of the UE, ephemeris informationassociated with the satellite, information provided by gateway (e.g., inbroadcast or unicast), time stamps of communications with the satellite,or any combinations thereof. In cases where the satellite timingreference is used for UE UL timing (e.g., in examples where the gNB is asatellite and not a ground gateway), the UE may calculate the RTD andtiming variation for RTD only between UE and satellite. In such cases,the UE may not consider the RTD variation between satellite and gateway.In some cases, the RTD between satellite and gateway may be broadcastfor initial access.

According to the techniques described herein, wireless communicationssystems (e.g., NTNs) may limit delays for UL communications (e.g., limitoffsets between a UE UL frame timing structure and a UE DL frame timingstructure). For instance, when a UE receives a grant (e.g., at 410 for‘Close UE’ and at 415 for ‘Far UE’), wireless communications systems maylimit the duration between the received grant and corresponding ULtransmission (e.g., at 425 for ‘Close UE’ and at 420 for ‘Far UE’). Thatis, when a UE receives a grant and starts processing when to transmit UL(e.g., such as transmission of PUSCH corresponding to an UL grant orhybrid automatic repeat request (HARQ)-ACK corresponding to a DL grant)the network may impose buffering limits to some number of slots or sometime duration (e.g., in ms).

FIG. 5 illustrates an example of a frame timing diagram 500 thatsupports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure. In someexamples, frame timing diagram 500 may implement aspects of wirelesscommunication system 100, wireless communications system 200, frametiming diagram 300, frame timing diagram 301, timing diagram 400, and/ortiming diagram 401. For example, frame timing diagram 500 may be basedon a configuration by a gateway 105 (or a satellite 120), andimplemented by a UE 115 for estimating and determining UL timing (orimplemented by a satellite 120 for estimating and determining DL timing)in an NTN, as described with reference to FIGS. 1-4. Generally, FIG. 5may illustrate one or more aspects that may allow frameworks (e.g.,NTNs) to define timing relationships at a base station (gNB, which mayrefer to a gateway and/or a satellite) and a UE based on timing fullyaligned at the network 525.

In the example of FIG. 5, a satellite may schedule the UE to transmit anUL transmission in satellite DL slot0 of sat DL 510 timing. In somecases, sat DL 510 timing may be aligned with sat UL 505 timing (e.g.,satellite UL slot 0). Based on a scheduling offset (K_(offset)=N) and aTA, UEs may determine an UL radio frame timing structure (e.g., UE UL515 timing) such that UE UL may be transmitted according to a TA forsatellite reception of the UL message in the frame where the satelliteexpects to receive the UL message (e.g., such that the UL transmissionfrom the UE arrives at the satellite aligned with a frame boundaryexpected for DL scheduling in satellite DL slot0). For instance, in somecases a network 525 may implement a K2 offset for UL (e.g., PUSCH)communications scheduled by a downlink (e.g., PDCCH) grant. In somecases, K2=3 slots, and a satellite scheduling an UL transmission via aDL slot0 may expect to receive a corresponding UL message (e.g., PUSCH,HARQ-ACK, etc.) in an UL s1ot3. In such cases, UEs may determine an ULradio frame timing structure (e.g., UE UL 515 timing) based on ascheduling offset (K_(offset)=N), slot offset (K2=3), and a TA, suchthat UE UL (e.g., an UL message) may be transmitted according to a TAfor satellite reception of the UL message in the slot where thesatellite expects to receive the UL message (e.g., in a satellite ULs1ot3 of sat UL 505).

According to the techniques described herein, UEs may receive anindication of a scheduling offset, K_(offset)=N, from a gNB (e.g., abase station or satellite). UEs may then determine an RTT forcommunications with the gNB and determine a TA based on K_(offset)=N andthe determined RTT. As such, UEs with various delays (e.g., differentRTTs) within the cell may transmit UL messages to the gNB in accordancewith timing alignment at the network 525. In the example frame timingdiagram 500, K_(offset)=N, TA=N_(X), and TA for PRACH=N_(X) (e.g., theTA used for PUSCH and PRACH may be the UE-specific RTT, which may bedetermined by the UE or signaled by the satellite in RTD information).

K_(offset) may refer to a scheduling offset (e.g., from 0-32 slots, ormore slots for NTNs). K_(offset) may be signaled to UEs in the cell viaSIB or other signaling. As an example, without K_(offset), for 15kilohertz (kHz) SCS and a 30 ms (30 slot) scheduling delay, if TA=200ms, then an UL message corresponding to a grant received in a slot s (orSFN s) may be transmitted in a slot s−170+K, where K may be indicated inthe DCI and may indicate an additional offset on top of the schedulingoffset. As such, NTNs may implement K_(offset) such that if a baselineTA (e.g., N) is present, the scheduling delay starts at the baseline TA(e.g., N) via implementation of the K_(offset)=N, where N corresponds tothe worst case RTT, as described herein. Therefore, UEs with delaysother than the worst case RTT (N) may adjust their radio frame timingstructure or UL timing such that their TA accounts for their N_(X)(e.g., via TA=N−N_(X), or TA=N−D for the UE with the minimum delay inthe cell 535). For example, a UE with a minimum delay (D slotsdifference) 535 may have a UE DL 520-b timing that is behind a UE UL515-b by a minimum TA (e.g., TA_min (N-D slots) 550.

K_(offset) and TA may thus offset each other to some extent depending onthe best case scenario RTT of the cell and a particular UE's RTT incomparison to the best case RTT captured by K_(offset) (e.g., a UE withmax delay 530 in cell applies TA_(Max) of N slots). K_(offset)=N may beincluded as a part of UE radio frame timing structure such that TA=N isapplied (e.g., to align UL frame N with DL frame 0 for the UE withmaximum delay 530 within the cell). Further, the described techniquesmay limit TA and K_(offset) to limit buffering, improve systemefficiency, etc. (e.g., otherwise if K_(offset) is too large and if TAis small, then the UE has to buffer for a very long time).

The gNB (e.g., satellite) may signal a K_(offset)=N and UEs in the cellmay apply TA=N_(X) (e.g., plus, potentially, small TA commandcorrections). As discussed, the techniques described herein may limitthe buffering length at the UE (e.g., to D). The buffering length at theUE may be limited to, for example, X slots or X ms. In some examples,wireless communications systems (e.g., UEs and radio frame timingstructures in an NTN) may adhere to K_(offset)TA<delta (e.g., or morespecifically K_(offset)*slotDuration−TA<delta). In some cases, delta maybe specified or preconfigured by the network 525, may depend onnumerology, may depend on UE capability (e.g., UE buffering capability),etc. Additionally or alternatively, wireless communications systems(e.g., UEs and radio frame timing structures in an NTN, such as UE UL515-a timing and UE DL 520-a timing) may adhere toTA<K_(offset)+TA_(Max) (e.g., where TA_(Max) 540 may be preconfigured,signaled, or otherwise specified by the network 525). In some cases, thevalue of delta may depend on, for example, ephemeris information (e.g.,for geosynchronous orbit (GEO) it may be larger than for LEO, or MEO forexample).

FIG. 6 illustrates an example of a frame timing diagram 600 thatsupports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure. In someexamples, frame timing diagram 600 may implement aspects of wirelesscommunication system 100, wireless communications system 200, frametiming diagram 300, frame timing diagram 301, timing diagram 400, timingdiagram 401, and/or frame timing diagram 500. For example, frame timingdiagram 600 may be based on a configuration by a gateway 105 (or asatellite 120), and implemented by a UE 115 for estimating anddetermining UL timing (or implemented by a satellite 120 for estimatingand determining DL timing) in an NTN, as described with reference toFIGS. 1-5. Generally, FIG. 6 may illustrate one or more aspects that mayallow frameworks (e.g., NTNs) to define timing relationships at a basestation (gNB, which may refer to a gateway and/or a satellite) and a UEbased on timing aligned with offset.

In the example of FIG. 6, a satellite may schedule the UE to transmit anUL transmission in satellite DL slot0 of sat DL 610 timing. In somecases, sat DL 610 timing may be aligned with sat UL 605 timing (e.g.,satellite UL slot 0). Based on a scheduling offset (K_(offset)=D) and aTA (e.g., TA=N_(X)−(N−D)), UEs may determine an UL radio frame timingstructure (e.g., UE UL 615-a timing) such that UE UL may be transmittedaccording to a TA for satellite reception of the UL message in the framewhere the satellite expects to receive the UL message (e.g., such thatthe UL transmission from the UE arrives at the satellite aligned with aframe boundary expected for DL scheduling in satellite DL slot0 of satDL 610). For instance, in some cases a network 625 may implement a K2offset for UL (e.g., PUSCH) communications scheduled by a DL (e.g.,PDCCH) grant. Further, in some cases, K1 may refer to a time offsetbetween physical downlink shared channel (PDSCH) and HARQ-ACK (e.g.,physical uplink control channel (PUCCH) transmission). In some cases,K2=3 slots, and a satellite scheduling an UL transmission via a DL slot0may except to receive a corresponding UL message (e.g., PUSCH, HARQ-ACK,etc.) in an UL s1ot3. In such cases, UEs may determine an UL radio frametiming structure (e.g., UE UL timing) based on a scheduling offset(K_(offset)=N), slot offset (K2=3), and a TA, such that UE UL (e.g., anUL message) may be transmitted according to a TA for satellite receptionof the UL message in the frame where the satellite expects to receivethe UL message (e.g., in a satellite UL s1ot3 of sat UL 605).

According to the techniques described herein, UEs may receive anindication of a scheduling offset, K_(offset)=D, from a gNB (e.g., abase station or satellite). UEs may then determine an RTT forcommunications with the gNB and determine a TA based on K_(offset)=D andthe determined RTT. As such, UEs with various delays (e.g., differentRTTs) within the cell may transmit UL messages to the gNB in accordancewith timing alignment at the network 625. In the example frame timingdiagram 600, K_(offset)=D, TA=N_(X)−(N−D), the offset at thenetwork=N−D, and the TA for PRACH=N_(X)−(N−D).

As discussed, K_(offset) may refer to a scheduling offset (e.g., from0-32 slots, or more slots for NTNs). K_(offset) may be signaled to UEsin the cell via SIB or other signaling. As such, according to theexample of FIG. 6, NTNs may implement K_(offset) such that some delay isadded in the frame structure (the radio frame timing structure) of thenetwork 625. As all UEs may have a common delay of N−D 640 (e.g., theminimum delay or RTT of the cell), the network 625 may account for suchan offset and the UEs may account for differential delay from other UEsin the cell (e.g., instead of UEs having to do all the work, UEs mayaccount for differential delay within the cell and the satellite mayabsolve common delay within the cell).

The gNB (e.g., satellite) may signal a K_(offset) D in addition to acommon offset (N−D), and UEs in the cell may apply TA=N_(x)−(N−D),(e.g., plus, potentially, small TA command corrections). In suchexamples, there may be no need to add additional limitations in the TA(e.g., as the TA will be between 0 and D). In some cases, D for NTNs maybe larger than a TA_(Max) for terrestrial communications systems. Inexample frame timing diagram 600, UEs may use a common offset (N−D) 640in determining TA=N_(X)−(N−D), as the network 625 may be accounting forthe common offset delay (e.g., out of total UE RTT (N_(X)) gNB ishandling the common delay N−D 640 part of it). In some cases, if the RTTestimation is based on timestamps, then the network 625 (e.g., gNB orsatellite) may determine (or dynamically switch between) whether or notto use radio frame timing structures analogous to example frame timingdiagram 500 or example frame timing diagram 600 (e.g., when implementingradio frame timing structures analogous to example frame timing diagram600, the timestamps may be delayed by N−D).

Generally, considering UEs with GNSS and without GNSS, the UE mayidentify or determine (e.g., either via explicit signaling, via networkspecification or preconfiguration, or via derivation from otherparameters), a minimum offset (M), a scheduling slot offset (S), and aportion of the offset that is captured at the network side (P). Forimplementing radio frame timing structures analogous to example frametiming diagram 500 (e.g., where timing is fully aligned at the network625), M=N−D, S=N, and P=0. For implementing radio frame timingstructures analogous to example frame timing diagram 600 (e.g., wheretiming is aligned with an offset, such as with a common offset N−D),M=N−D, S=D, and P=N−D. In some cases, a minimum offset may beimplemented for UEs without GNSS for initial TA for PRACH. For example,the UE UL 615-b timing and UE DL 620-b timing may be aligned for a UEwith a minimum delay 635.

In some cases, relationships between M, S, and P (as well as the TA) maybe limited by wireless communications systems (e.g., by NTNs). Forexample, wireless communications systems (e.g., UEs and radio frametiming structures in an NTN) may adhere to S+P−M<z, where z may bespecified or preconfigured by the network 625, where z may depend ondeployment, etc. (e.g., which may limit buffering at the UE, forinstance, by limiting the max time between receiving a DCI andtransmitting PUSCH). Additionally or alternatively, wirelesscommunications systems (e.g., UEs and radio frame timing structures inan NTN) may adhere to M−P<TA<M−P+y, where y may be specified orpreconfigured by the network 625, where y may depend on deployment, etc.(e.g., which may limit the range of TA at the UE). In some cases, the UEUL 615-a timing and the UE DL 620-a timing for a UE with maximum delay630 may be offset by a maximum TA (e.g., TA_max (D slots) 645).

FIG. 7 illustrates an example of a frame timing diagram 700 thatsupports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure. In someexamples, frame timing diagram 700 may implement aspects of wirelesscommunication system 100, wireless communications system 200, frametiming diagram 300, frame timing diagram 301, timing diagram 400, timingdiagram 401, and/or frame timing diagram 500. For example, frame timingdiagram 700 may be based on a configuration by a gateway 105 (or asatellite 120), and implemented by a UE 115 for estimating anddetermining UL timing (or implemented by a satellite 120 for estimatingand determining DL timing) in an NTN, as described with reference toFIGS. 1-5. Generally, FIG. 7 may illustrate one or more aspects that mayallow frameworks (e.g., NTNs) to define timing relationships at a basestation (gNB, which may refer to a gateway and/or a satellite) and a UEbased on UE alignment with a closest slot.

In the example of FIG. 7, a satellite may schedule the UE to transmit anUL transmission in satellite DL slot0 of sat DL 710 where K_(offset)=0.In such cases, TA may be rounded down to a nearest slot boundary and UEsmay determine an UL radio frame timing structure (e.g., UE UL 715timing) such that UE UL may be transmitted according to a nearest slotboundary and the satellite may account for differences in RTTsassociated with different UEs in the cell. If network 725 schedules thetwo UEs (e.g., UE with a maximum delay 730, UE with a minimum delay 735)at DL slot0, the network 725 may receive UL from the different UEs atdifferent times. A UE with a maximum delay 730 may be configured with aUE UL 715-a timing and a UE DL 720-a timing that may be aligned oroffset. A UE with a minimum delay 735 may be configured with a UE UL715-b timing and a UE DL 720-b timing that may be aligned or offset. Inother words, the offset at the network 725 may be different fordifferent UEs. In such examples where timing is aligned at the UEs andthe network 725 manages differences in reception timing, the TA forPRACH and Msg3 may be N_(X) 745 (or (N_(X)−D) 740), as during initialaccess the network 725 may be able to estimate when Msg3 will arrivefrom served UEs. As such, Msg3 from UEs may include indication of TA andslot offset.

For example, when performing random access, the UE may know the RTTdelay N_(X). For a RACH occasion in “gNB UL slot” n, the gNB maytransmit in “UE UL slot n−N_(X)”. When sending the random accessresponse, the gNB may not know the TA applied by the UE. So, the gNB maysignal a “fractional TA” to be applied. The “fractional TA” may be, insome cases, a time difference between the received PRACH and the closestslot boundary. The random access response may schedule a PUSCH (msg3) in“gNB UL slot s” (e.g., the UE may delay its transmission by N−N_(X)+TAon top of the scheduling delay such that all the UEs may transmit in thesame UL slot). In msg3, the UE may include the N−N_(X) (in slots). Now,the gNB may determine the relationship between a grant and thecorresponding UL transmission. For the rest of the transmissions, the UEmay disregard K_(offset) or max RTT (e.g., the UL and DL frames may beshifted only by the TA).

In some examples, the scrambling sequence, PUSCH hopping, etc. may bechanged or updated to align the values transmitted by multiple UEs(e.g., apply the K_(offset) and N_(X) to the slot in the sequenceinitialization). In some examples, TA may be greater than zero (TA>0)during the connection. When the TA is moving very close to 0, the gNBmay issue a command to “shift the frame structure” by, for example, 1slot and keep the TA positive.

FIG. 8 illustrates an example of a process flow 800 that supports timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure. In some examples, processflow 800 may implement aspects of wireless communication system 100,wireless communications system 200, frame timing diagram 300, frametiming diagram 301, timing diagram 400, timing diagram 401, frame timingdiagram 500, frame timing diagram 600, and/or frame timing diagram 700(e.g., as described with reference to FIGS. 1-7). For example, theprocess flow 800 may be based on a configuration by a network, andimplemented by a UE for identifying propagation delay, radio frametiming structure, etc. for use in determining DL and UL timing in anNTN, or some other network, as described with reference to FIGS. 1-7.

The process flow 800 may include a first device 801 and a second device802. First device 801 may be an example of a UE or base station, andsecond device 802 may be an example of a satellite or base station,which may be examples of a gNB (or base station 105) and a UE 115 asdescribed with reference to FIGS. 1-7. For example, second device 802may be an example of a satellite 120, a ground base station 105 orgateway, etc., as described herein. In the following description of theprocess flow 800, the operations between the second device 801 and thefirst device 801 may be performed in a different order than the exampleorder shown, or the operations performed by the second device 802 andthe first device 801 may be performed in different orders or atdifferent times. Some operations may also be omitted from the processflow 800, and other operations may be added to the process flow 800. Inthe example of FIG. 8, the second device 802 and the first device 801may be in communication with each other via an NTN. The process flow 800may support improved timing, higher data rates, improved mobilitysupport for the first device 801 in the NTN, among other benefits.

At 805, the second device 802 may determine to use the satellite timereference for communications with the first device 801. At 810, thesecond device 802 may transmit configuration information to the firstdevice 801 that indicates that the satellite time reference is to beused for UL communications timing of the first device 801. In someexamples, the configuration information may include an indication of ascheduling offset (K_(offset)) between a DL radio frame timing structureand an UL radio frame timing structure. In some cases, the configurationinformation may be provided in broadcast transmissions from the seconddevice 802, such as in one or more SIBs. At 810, the first device 801may identify the satellite time reference is to be used for UL timingdetermination. In some cases, the first device 801 may decode broadcastinformation that indicates to use the satellite time reference (e.g., aswell as an indication of K_(offset)). In some cases, the configurationinformation may include RTD information (e.g., a propagation delayvalue, a common offset N−D, etc.). In some cases, the configurationinformation may generally include indication of any of M, P, S, delta,TA_(Max), y, and z, as described herein.

At 815, first device 801 may determine a RTT for communications with thesecond device 802. At 820, first device 801 may determine a TA based onthe scheduling offset and the RTT (e.g., an potentially otherinformation in the configuration information received at 810). At 825,first device 801 may transmit an UL message (e.g., PUSCH, HARQ feedback,etc.) to the second device 802 in accordance with the techniquesdescribed herein (e.g., based on radio frame timing structure, TAapplication, etc.). For example, in some cases, first device 801 maydetermine a range of TA values based on S+P−M<z, M−P<TA<M−P+y,K_(offset) TA<delta, TA<K_(offset)+TA_(Max), or some combinationthereof. The first device 801 may determine a TA, in accordance with anyconfigured thresholds described herein, and apply the TA to ULtransmission timing (e.g., based on radio frame timing structuresdescribed herein).

FIG. 9 illustrates an example of a process flow 900 that supports timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure. In some examples, processflow 900 may implement aspects of wireless communication system 100,wireless communications system 200, frame timing diagram 300, frametiming diagram 301, timing diagram 400, timing diagram 401, frame timingdiagram 500, frame timing diagram 600, frame timing diagram 700, and/orprocess flow 800 (e.g., as described with reference to FIGS. 1-8). Forexample, the process flow 900 may be based on a configuration by anetwork, and implemented by a UE for identifying propagation delay,radio frame timing structure, etc. for use in determining DL and ULtiming in an NTN, or some other network, as described with reference toFIGS. 1-8.

The process flow 900 may include a first device 901 and a second device902. First device 901 may be an example of a UE or base station, andsecond device 902 may be an example of a satellite or base station,which may be examples of a gNB (or base station 105) and a UE 115 asdescribed with reference to FIGS. 1-8. For example, second device 902may be an example of a satellite 120, a ground base station 105 orgateway, etc., as described herein. In the following description of theprocess flow 900, the operations between the second device 902 and thefirst device 901 may be performed in a different order than the exampleorder shown, or the operations performed by the second device 902 andthe first device 901 may be performed in different orders or atdifferent times. Some operations may also be omitted from the processflow 900, and other operations may be added to the process flow 900. Inthe example of FIG. 9, the second device 902 and the first device 901may be in communication with each other via an NTN. The process flow 900may support improved timing, higher data rates, improved mobilitysupport for the first device 901 in the NTN, among other benefits.

At 905, first device 901 may transmit a RACH preamble (e.g., RACH Msgl)to second device 902 for an initial access procedure. At 910, seconddevice 902 may transmit a random access response (e.g., a RAR or RACHresponse) to the first device 901. In some examples, the RAR message at910 may include a fraction TA (e.g., a fractional TA to align asubsequent RACH Msg3 with a slot boundary of second device 902 radioframe timing structure, where the fractional TA is based on thereception timing of the RACH preamble at 905). At 915, first device 901may determine a differential offset between a first slot boundaryassociated with a base station radio frame timing structure and a secondslot boundary associated with a UE radio frame timing structure (e.g.,based on the fractional TA). At 920, first device 901 may transmit, tothe second device 902 in response to the RAR message, a second randomaccess message (e.g., a Msg3) including the differential offset. In someexamples, process flow may illustrate one or more aspects of techniques(e.g., RACH techniques) described with reference to FIG. 7.

FIG. 10 shows a block diagram 1000 of a device 1005 that supports timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure. The device 1005 may be anexample of aspects of a UE 115 as described herein. The device 1005 mayinclude a receiver 1010, a communications manager 1015, and atransmitter 1020. The device 1005 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

The receiver 1010 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to timingimprovements for wireless communications systems, etc.). Information maybe passed on to other components of the device 1005. The receiver 1010may be an example of aspects of the transceiver 1320 described withreference to FIG. 13. The receiver 1010 may utilize a single antenna ora set of antennas.

The communications manager 1015 may receive, from a base station, anindication of a scheduling offset between a DL radio frame timingstructure and an UL radio frame timing structure, and transmit an ULmessage to the base station based on the TA, the TA based on thereceived indication of the scheduling offset.

The communications manager 1015 may also receive, from a base station, arandom access response message including a fractional TA. Thecommunications manager 1015 may transmit, to the base station inresponse to the random access response message, a second random accessmessage including a differential offset between a first slot boundaryassociated with a base station radio frame timing structure and a secondslot boundary associated with a UE radio frame timing structure.

The communications manager 1015 may be an example of aspects of thecommunications manager 1310 described herein. The communications manager1015, or its sub-components, may be implemented in hardware, code (e.g.,software or firmware) executed by a processor, or any combinationthereof. If implemented in code executed by a processor, the functionsof the communications manager 1015, or its sub-components may beexecuted by a general-purpose processor, a digital signal processor(DSP), an application-specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described in thepresent disclosure.

The communications manager 1015 may be an example of means forperforming various aspects of timing determination procedures asdescribed herein. The communications manager 1015, or itssub-components, may be implemented in hardware (e.g., in communicationsmanagement circuitry). The circuitry may comprise one or more of aprocessor, a DSP, an ASIC, a FPGA or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described in thepresent disclosure.

In another implementation, the communications manager 1015, or itssub-components, may be implemented in code (e.g., as communicationsmanagement software or firmware) executed by a processor, or anycombination thereof. If implemented in code executed by a processor, thefunctions of the communications manager 1015, or its sub-components maybe executed by a general-purpose processor, a DSP, an ASIC, an FPGA orother programmable logic device.

In some examples, the communications manager 1015 may be configured toperform various operations (e.g., receiving, transmitting) using orotherwise in cooperation with the receiver 1010, the transmitter 1020,or both.

The communications manager 1015, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 1015, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 1015, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an input/output (I/O)component, a transceiver, a network server, another computing device,one or more other components described in the present disclosure, or acombination thereof in accordance with various aspects of the presentdisclosure.

The described techniques, such as those described with reference to acommunications manager 1015, may support NTN timing alignment ofcommunications between a base station or satellite and one or more UEsserved by the base station or satellite. For instance, the describedtechniques may provide for reliable estimation of timing offsets, andreliable estimation of TA values for UL, etc. relating to communicationsbetween high-altitude vehicles (e.g., satellites or othernon-terrestrial-based equipment), user terminals, and gateways, in NTNs.As such, supported techniques may include features for efficient NTNsand efficient non-terrestrial communications. The described techniquesmay also support increased spectral efficiency and, in some examples,may promote higher mobility support for user terminals in NTNs comparedto terrestrial networks.

The transmitter 1020 may transmit signals generated by other componentsof the device 1005. In some examples, the transmitter 1020 may becollocated with a receiver 1010 in a transceiver module. For example,the transmitter 1020 may be an example of aspects of the transceiver1320 described with reference to FIG. 13. The transmitter 1020 mayutilize a single antenna or a set of antennas.

FIG. 11 shows a block diagram 1100 of a device 1105 that supports timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure. The device 1105 may be anexample of aspects of a device 1005, or a UE 115 as described herein.The device 1105 may include a receiver 1110, a communications manager1115, and a transmitter 1150. The device 1105 may also include aprocessor. Each of these components may be in communication with oneanother (e.g., via one or more buses).

The receiver 1110 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to timingimprovements for wireless communications systems, etc.). Information maybe passed on to other components of the device 1105. The receiver 1110may be an example of aspects of the transceiver 1320 described withreference to FIG. 13. The receiver 1110 may utilize a single antenna ora set of antennas.

The communications manager 1115 may be an example of aspects of thecommunications manager 1015 as described herein. The communicationsmanager 1115 may include a scheduling offset manager 1120, a RTT manager1125, a TA manager 1130, an uplink manager 1135, a RACH manager 1140,and a differential offset manager 1145. The communications manager 1115may be an example of aspects of the communications manager 1310described herein.

The scheduling offset manager 1120 may receive, from a base station, anindication of a scheduling offset between a DL radio frame timingstructure and an UL radio frame timing structure. The RTT manager 1125may determine a RTT for communications with the base station. The TAmanager 1130 may determine a TA based on the scheduling offset and theRTT. The uplink manager 1135 may transmit an UL message to the basestation based on the TA, the TA based on the received indication of thescheduling offset.

The RACH manager 1140 may receive, from a base station, a random accessresponse message including a fractional TA. The differential offsetmanager 1145 may determine a differential offset between a first slotboundary associated with a base station radio frame timing structure anda second slot boundary associated with a UE radio frame timingstructure. The RACH manager 1140 may transmit, to the base station inresponse to the random access response message, a second random accessmessage including the differential offset between a first slot boundaryassociated with a base station radio frame timing structure and a secondslot boundary associated with a UE radio frame timing structure.

The transmitter 1150 may transmit signals generated by other componentsof the device 1105. In some examples, the transmitter 1150 may becollocated with a receiver 1110 in a transceiver module. For example,the transmitter 1150 may be an example of aspects of the transceiver1320 described with reference to FIG. 13. The transmitter 1150 mayutilize a single antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a communications manager 1205 thatsupports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure. Thecommunications manager 1205 may be an example of aspects of acommunications manager 1015, a communications manager 1115, or acommunications manager 1310 described herein. The communications manager1205 may include a scheduling offset manager 1210, a RTT manager 1215, aTA manager 1220, an uplink manager 1225, a node orbit manager 1230, acommon offset manager 1235, a network offset manager 1240, a RACHmanager 1245, and a differential offset manager 1250. Each of thesemodules may communicate, directly or indirectly, with one another (e.g.,via one or more buses).

The scheduling offset manager 1210 may receive, from a base station, anindication of a scheduling offset between a DL radio frame timingstructure and an UL radio frame timing structure.

The RTT manager 1215 may determine a RTT for communications with thebase station. In some examples, the RTT manager 1215 may determine a RTTfor communications with a base station. In some examples, the RTTmanager 1215 may determine a scrambling sequence, a hopping pattern, orboth based on the RTT. In some cases, the RTT for communications withthe base station is determined based on one or more of a position of theUE, a position of the base station, a distance between the UE and thebase station, a timestamp corresponding to a DL message received fromthe base station, and a local timestamp.

The TA manager 1220 may determine a TA based on the scheduling offsetand the RTT. In some examples, the TA manager 1220 may determine a rangeof TA values based on the scheduling offset, where the TA is determinedbased on the range. In some examples, the TA manager 1220 may determinea TA threshold, where the TA is determined based on the TA threshold. Insome examples, the TA manager 1220 may determine a range of TA valuesbased on the common offset, where the TA is determined based on therange. In some examples, the TA manager 1220 may determine a range of TAvalues based on the network offset, where the TA is determined based onthe range. In some examples, the TA manager 1220 may determine aninitial TA based on the minimum offset. In some examples, the TA manager1220 may determine a TA based on the differential offset. In some cases,the TA threshold is determined based on one or more of a slot duration,a radio frame numerology, and a buffering capability of the UE.

The uplink manager 1225 may transmit an UL message to the base stationbased on the TA, the TA based on the received indication of thescheduling offset. In some examples, the uplink manager 1225 maytransmit a PRACH channel message based on the initial TA. In someexamples, the uplink manager 1225 may transmit an UL message to the basestation based on the TA.

The RACH manager 1245 may receive, from a base station, a random accessresponse message including a fractional TA. In some examples, the RACHmanager 1245 may transmit, to the base station in response to the randomaccess response message, a second random access message including adifferential offset between a first slot boundary associated with a basestation radio frame timing structure and a second slot boundaryassociated with a UE radio frame timing structure. In some examples, theRACH manager 1245 may transmit a first random access message to the basestation based on the RTT, where the random access response message isreceived based on transmitting the first random access message.

The differential offset manager 1250 may determine a differential offsetbetween a first slot boundary associated with a base station radio frametiming structure and a second slot boundary associated with a UE radioframe timing structure. In some examples, the differential offsetmanager 1250 may receive, from the base station, an indication to shiftthe UE radio frame timing structure. In some examples, the differentialoffset manager 1250 may shift the UE radio frame timing structure basedon the indication, where the TA is determined based on the shifting. Insome cases, the differential offset is determined based on thefractional TA.

The node orbit manager 1230 may determine an orbit type associated withthe base station, where the range is determined based on the orbit type.

The common offset manager 1235 may receive an indication of a commonoffset associated with a cell served by the base station, where the TAis determined based on the common offset.

The network offset manager 1240 may determine a network offset between anetwork DL radio frame timing structure and a network UL radio frametiming structure, where the TA is determined based on the networkoffset. In some examples, the network offset manager 1240 may receive anindication of the network offset, where the network offset is determinedbased on the indication of the network offset. In some examples, thenetwork offset manager 1240 may determine a minimum offset between theDL radio frame timing structure and the UL radio frame timing structure,where the TA is determined based on the minimum offset.

FIG. 13 shows a diagram of a system 1300 including a device 1305 thatsupports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure. Thedevice 1305 may be an example of or include the components of device1005, device 1105, or a UE 115 as described herein. The device 1305 mayinclude components for bi-directional voice and data communicationsincluding components for transmitting and receiving communications,including a communications manager 1310, an I/O controller 1315, atransceiver 1320, an antenna 1325, memory 1330, and a processor 1340.These components may be in electronic communication via one or morebuses (e.g., bus 1345).

The communications manager 1310 may receive, from a base station, anindication of a scheduling offset between a DL radio frame timingstructure and an UL radio frame timing structure, and transmit an ULmessage to the base station based on a TA, the TA based on the receivedindication of the scheduling offset.

The communications manager 1310 may also receive, from a base station, arandom access response message including a fractional TA. Thecommunications manager 1310 may transmit, to the base station inresponse to the random access response message, a second random accessmessage including a differential offset between a first slot boundaryassociated with a base station radio frame timing structure and a secondslot boundary associated with a UE radio frame timing structure.

The I/O controller 1315 may manage input and output signals for thedevice 1305. The I/O controller 1315 may also manage peripherals notintegrated into the device 1305. In some cases, the I/O controller 1315may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 1315 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 1315may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 1315may be implemented as part of a processor. In some cases, a user mayinteract with the device 1305 via the I/O controller 1315 or viahardware components controlled by the I/O controller 1315.

The transceiver 1320 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1320 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1320 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1325.However, in some cases the device may have more than one antenna 1325,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1330 may include random-access memory (RAM) and read-onlymemory (ROM). The memory 1330 may store computer-readable,computer-executable code or software 1335 including instructions that,when executed, cause the processor to perform various functionsdescribed herein. In some cases, the memory 1330 may contain, amongother things, a basic I/O system (BIOS) which may control basic hardwareor software operation such as the interaction with peripheral componentsor devices.

The processor 1340 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1340 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 1340. The processor 1340 may beconfigured to execute computer-readable instructions stored in a memory(e.g., the memory 1330) to cause the device 1305 to perform variousfunctions (e.g., functions or tasks supporting timing improvements forwireless communications systems).

The software 1335 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The software 1335 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the software 1335 may not be directly executable by theprocessor 1340 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 14 shows a block diagram 1400 of a device 1405 that supports timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure. The device 1405 may be anexample of aspects of a base station 105 as described herein. The device1405 may include a receiver 1410, a communications manager 1415, and atransmitter 1420. The device 1405 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

The receiver 1410 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to timingimprovements for wireless communications systems, etc.). Information maybe passed on to other components of the device 1405. The receiver 1410may be an example of aspects of the transceiver 1720 described withreference to FIG. 17. The receiver 1410 may utilize a single antenna ora set of antennas.

The communications manager 1415 may transmit, to the UE, an indicationof a scheduling offset between a DL radio frame timing structure and anUL radio frame timing structure, and receive an UL message from the UEbased on a range of TA values, the range of TA values based on thescheduling offset. The communications manager 1415 may be an example ofaspects of the communications manager 1710 described herein.

The communications manager 1415, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 1415, or itssub-components may be executed by a general-purpose processor, a DSP, anASIC, a FPGA or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described in the presentdisclosure.

The communications manager 1415 may be an example of means forperforming various aspects of timing determination procedures asdescribed herein. The communications manager 1415, or itssub-components, may be implemented in hardware (e.g., in communicationsmanagement circuitry). The circuitry may comprise one or more of aprocessor, a DSP, an ASIC, a FPGA or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described in thepresent disclosure.

In another implementation, the communications manager 1415, or itssub-components, may be implemented in code (e.g., as communicationsmanagement software or firmware) executed by a processor, or anycombination thereof. If implemented in code executed by a processor, thefunctions of the communications manager 1415, or its sub-components maybe executed by a general-purpose processor, a DSP, an ASIC, an FPGA orother programmable logic device.

In some examples, the communications manager 1415 may be configured toperform various operations (e.g., receiving, transmitting) using orotherwise in cooperation with the receiver 1010, the transmitter 1020,or both.

The communications manager 1415, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 1415, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 1415, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an input/output (I/O)component, a transceiver, a network server, another computing device,one or more other components described in the present disclosure, or acombination thereof in accordance with various aspects of the presentdisclosure.

The described techniques, such as those described with reference tocommunications manager 1415, may support reliable NTN timing alignmentof communications between a base station or satellite and one or moreUEs served by the base station or satellite. For instance, the describedtechniques may provide for reliable estimation of timing offsets, andreliable estimation of TA values for UL, etc. relating to communicationsbetween high-altitude vehicles (e.g., satellites or othernon-terrestrial-based equipment), user terminals, and gateways, in NTNs.As such, supported techniques may include features for efficient NTNsand efficient non-terrestrial communications. The described techniquesmay also support increased spectral efficiency and, in some examples,may promote higher mobility support for user terminals in NTNs comparedto terrestrial networks.

The transmitter 1420 may transmit signals generated by other componentsof the device 1405. In some examples, the transmitter 1420 may becollocated with a receiver 1410 in a transceiver module. For example,the transmitter 1420 may be an example of aspects of the transceiver1720 described with reference to FIG. 17. The transmitter 1420 mayutilize a single antenna or a set of antennas.

FIG. 15 shows a block diagram 1500 of a device 1505 that supports timingimprovements for wireless communications systems in accordance with oneor more aspects of the present disclosure. The device 1505 may be anexample of aspects of a device 1405, or a base station 105 as describedherein. The device 1505 may include a receiver 1510, a communicationsmanager 1515, and a transmitter 1535. The device 1505 may also include aprocessor. Each of these components may be in communication with oneanother (e.g., via one or more buses).

The receiver 1510 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to timingimprovements for wireless communications systems, etc.). Information maybe passed on to other components of the device 1505. The receiver 1510may be an example of aspects of the transceiver 1720 described withreference to FIG. 17. The receiver 1510 may utilize a single antenna ora set of antennas.

The communications manager 1515 may be an example of aspects of thecommunications manager 1415 as described herein. The communicationsmanager 1515 may include a RTT manager 1520, a scheduling offset manager1525, and an uplink manager 1530. The communications manager 1515 may bean example of aspects of the communications manager 1710 describedherein.

The RTT manager 1520 may determine a minimum RTT for communications witha UE. The scheduling offset manager 1525 may transmit, to the UE, anindication of a scheduling offset between a DL radio frame timingstructure and an UL radio frame timing structure. The uplink manager1530 may receive an UL message from the UE based on a range of TAvalues, the range of TA values based on the scheduling offset.

The transmitter 1535 may transmit signals generated by other componentsof the device 1505. In some examples, the transmitter 1535 may becollocated with a receiver 1510 in a transceiver module. For example,the transmitter 1535 may be an example of aspects of the transceiver1720 described with reference to FIG. 17. The transmitter 1535 mayutilize a single antenna or a set of antennas.

FIG. 16 shows a block diagram 1600 of a communications manager 1605 thatsupports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure. Thecommunications manager 1605 may be an example of aspects of acommunications manager 1415, a communications manager 1515, or acommunications manager 1710 described herein. The communications manager1605 may include a RTT manager 1610, a scheduling offset manager 1615,an uplink manager 1620, a TA manager 1625, a node orbit manager 1630, acommon offset manager 1635, and a network offset manager 1640. Each ofthese modules may communicate, directly or indirectly, with one another(e.g., via one or more buses).

The RTT manager 1610 may determine a minimum RTT for communications witha UE.

The scheduling offset manager 1615 may transmit, to the UE, anindication of a scheduling offset between a DL radio frame timingstructure and an UL radio frame timing structure. In some examples, thescheduling offset manager 1615 may determine a minimum offset betweenthe DL radio frame timing structure and the UL radio frame timingstructure, where the TA is determined based on the minimum offset.

The uplink manager 1620 may receive an UL message from the UE based on arange of TA values, the range of TA values based on the schedulingoffset. In some examples, the uplink manager 1620 may receive a PRACHmessage from the UE based on the initial TA.

The TA manager 1625 may determine a range of TA values based on thescheduling offset, where the UL message is received from the UE based onthe range. In some examples, the TA manager 1625 may determine a TAthreshold, where the TA is determined based on the TA threshold. In someexamples, the TA manager 1625 may determine an initial TA based on theminimum offset. In some cases, the TA threshold is determined based onone or more of a slot duration, a radio frame numerology, and abuffering capability of the UE.

The node orbit manager 1630 may determine an orbit type associated withthe base station, where the range is determined based on the orbit type.

The common offset manager 1635 may determine a common offset associatedwith a cell served by the base station. In some examples, the commonoffset manager 1635 may transmit an indication of the common offset tothe UE, where the UL message is received from the UE based on the commonoffset.

The network offset manager 1640 may determine a network offset between anetwork DL radio frame timing structure and a network UL radio frametiming structure, where the UL message is received from the UE based onthe network offset. In some examples, the network offset manager 1640may transmit an indication of the network offset to the UE.

FIG. 17 shows a diagram of a system 1700 including a device 1705 thatsupports timing improvements for wireless communications systems inaccordance with one or more aspects of the present disclosure. Thedevice 1705 may be an example of or include the components of device1405, device 1505, or a base station 105 as described herein. The device1705 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, including a communications manager 1710, a networkcommunications manager 1715, a transceiver 1720, an antenna 1725, memory1730, a processor 1740, and an inter-station communications manager1745. These components may be in electronic communication via one ormore buses (e.g., bus 1750).

The communications manager 1710 may transmit, to the UE, an indicationof a scheduling offset between a DL radio frame timing structure and anUL radio frame timing structure, and receive an UL message from the UEbased on a range of TA values, the range of TA values based on thescheduling offset.

The network communications manager 1715 may manage communications withthe core network (e.g., via one or more wired backhaul links). Forexample, the network communications manager 1715 may manage the transferof data communications for client devices, such as one or more UEs 115.

The transceiver 1720 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1720 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1720 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1725.However, in some cases the device may have more than one antenna 1725,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1730 may include RAM, ROM, or a combination thereof. Thememory 1730 may store computer-readable code or software 1735 includinginstructions that, when executed by a processor (e.g., the processor1740) cause the device to perform various functions described herein. Insome cases, the memory 1730 may contain, among other things, a BIOSwhich may control basic hardware or software operation such as theinteraction with peripheral components or devices.

The processor 1740 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1740 may be configured to operate a memoryarray using a memory controller. In some cases, a memory controller maybe integrated into processor 1740. The processor 1740 may be configuredto execute computer-readable instructions stored in a memory (e.g., thememory 1730) to cause the device 1705 to perform various functions(e.g., functions or tasks supporting timing improvements for wirelesscommunications systems).

The inter-station communications manager 1745 may manage communicationswith other base station 105, and may include a controller or schedulerfor controlling communications with UEs 115 in cooperation with otherbase stations 105. For example, the inter-station communications manager1745 may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, the inter-station communications manager1745 may provide an X2 interface within an LTE/LTE-A wirelesscommunication network technology to provide communication between basestations 105.

The software 1735 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The software 1735 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the software 1735 may not be directly executable by theprocessor 1740 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 18 shows a flowchart illustrating a method 1800 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 1800 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 1800 may beperformed by a communications manager as described with reference toFIGS. 10 through 13. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 1805, the UE may receive, from a base station, an indication of ascheduling offset between a DL radio frame timing structure and an ULradio frame timing structure. The operations of 1805 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1805 may be performed by a scheduling offset manageras described with reference to FIGS. 10 through 13.

At 1810, the UE may transmit an UL message to the base station based ona TA, the TA based on the received indication of the scheduling offset.The operations of 1810 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1810may be performed by an uplink manager as described with reference toFIGS. 10 through 13.

FIG. 19 shows a flowchart illustrating a method 1900 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 1900 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 1900 may beperformed by a communications manager as described with reference toFIGS. 10 through 13. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 1905, the UE may receive, from a base station, an indication of ascheduling offset between a DL radio frame timing structure and an ULradio frame timing structure. The operations of 1905 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1905 may be performed by a scheduling offset manageras described with reference to FIGS. 10 through 13.

At 1910, the UE may determine a range of TA values based on thescheduling offset, where a TA is determined based on the range. Theoperations of 1910 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1910 may beperformed by a TA manager as described with reference to FIGS. 10through 13.

At 1915, the UE may transmit an UL message to the base station based onthe TA, the TA based on the received indication of the schedulingoffset. The operations of 1915 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1915may be performed by an uplink manager as described with reference toFIGS. 10 through 13.

FIG. 20 shows a flowchart illustrating a method 2000 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 2000 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 2000 may beperformed by a communications manager as described with reference toFIGS. 10 through 13. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 2005, the UE may receive, from a base station, an indication of ascheduling offset between a DL radio frame timing structure and an ULradio frame timing structure. The operations of 2005 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2005 may be performed by a scheduling offset manageras described with reference to FIGS. 10 through 13.

At 2010, the UE may receive an indication of a common offset associatedwith a cell served by the base station, where the TA is determined basedon the common offset. The operations of 2010 may be performed accordingto the methods described herein. In some examples, aspects of theoperations of 2010 may be performed by a common offset manager asdescribed with reference to FIGS. 10 through 13.

At 2015, the UE may determine a network offset between a network DLradio frame timing structure and a network UL radio frame timingstructure, where the TA is determined based on the network offset. Theoperations of 2015 may be performed according to the methods describedherein. In some examples, aspects of the operations of 2015 may beperformed by a network offset manager as described with reference toFIGS. 10 through 13.

At 2020, the UE may determine a range of TA values based on thescheduling offset, the common offset, network offset, or somecombination thereof. For example, the UE may determine a range of TAvalues based on a delta value, an upper TA limit, a TA threshold, etc.in accordance with the techniques described herein (e.g., which may bespecified or configured by the network). The operations of 2020 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2020 may be performed by a TA manager asdescribed with reference to FIGS. 10 through 13.

At 2025, the UE may determine a TA based on the range. For example, theUE may determine a TA based on the scheduling offset and the determinedRTT (e.g., while adhering to the range determined at 2025). Theoperations of 2025 may be performed according to the methods describedherein. In some examples, aspects of the operations of 2025 may beperformed by a TA manager as described with reference to FIGS. 10through 13.

At 2030, the UE may transmit an UL message to the base station based onthe TA, the TA based on the received indication of the schedulingoffset. The operations of 2030 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 2030may be performed by an uplink manager as described with reference toFIGS. 10 through 13.

FIG. 21 shows a flowchart illustrating a method 2100 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 2100 may be implemented by a base station 105 or its componentsas described herein. For example, the operations of method 2100 may beperformed by a communications manager as described with reference toFIGS. 14 through 17. In some examples, a base station may execute a setof instructions to control the functional elements of the base stationto perform the functions described below. Additionally or alternatively,a base station may perform aspects of the functions described belowusing special-purpose hardware.

At 2105, the base station may transmit, to the UE, an indication of ascheduling offset between a DL radio frame timing structure and an ULradio frame timing structure. The operations of 21105 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2105 may be performed by a scheduling offset manageras described with reference to FIGS. 14 through 17.

At 2110, the base station may receive an UL message from the UE based ona range of TA values, the range of TA values based on the schedulingoffset. The operations of 2110 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 2110may be performed by an uplink manager as described with reference toFIGS. 14 through 17.

FIG. 22 shows a flowchart illustrating a method 2200 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 2200 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 2200 may beperformed by a communications manager as described with reference toFIGS. 10 through 13. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 2205, the UE may receive, from a base station, a random accessresponse message including a fractional TA. The operations of 2205 maybe performed according to the methods described herein. In someexamples, aspects of the operations of 2205 may be performed by a RACHmanager as described with reference to FIGS. 10 through 13.

At 2210, the UE may transmit, to the base station in response to therandom access response message, a second random access message includinga differential offset between a first slot boundary associated with abase station radio frame timing structure and a second slot boundaryassociated with a UE radio frame timing structure. The operations of2210 may be performed according to the methods described herein. In someexamples, aspects of the operations of 2210 may be performed by a RACHmanager as described with reference to FIGS. 10 through 13.

FIG. 23 shows a flowchart illustrating a method 2300 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 2300 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 2300 may beperformed by a communications manager as described with reference toFIGS. 10 through 13. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 2305, the UE may receive, from a base station, an indication of ascheduling offset between a downlink radio frame timing structure and anuplink radio frame timing structure. The operations of 2305 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2305 may be performed by a schedulingoffset manager as described with reference to FIGS. 10 through 13.

At 2310, the UE may determine a round trip time for communications withthe base station. The operations of 2310 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 2310 may be performed by a RTT manager as described withreference to FIGS. 10 through 13.

At 2315, the UE may determine a timing advance based on the schedulingoffset and the round trip time. The operations of 2315 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2315 may be performed by a TA manager as describedwith reference to FIGS. 10 through 13.

At 2320, the UE may transmit an uplink message to the base station basedon the timing advance. The operations of 2320 may be performed accordingto the methods described herein. In some examples, aspects of theoperations of 2320 may be performed by an uplink manager as describedwith reference to FIGS. 10 through 13.

FIG. 24 shows a flowchart illustrating a method 2400 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 2400 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 2400 may beperformed by a communications manager as described with reference toFIGS. 10 through 13. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 2405, the UE may receive, from a base station, an indication of ascheduling offset between a downlink radio frame timing structure and anuplink radio frame timing structure. The operations of 2405 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2405 may be performed by a schedulingoffset manager as described with reference to FIGS. 10 through 13.

At 2410, the UE may determine a round trip time for communications withthe base station. The operations of 2410 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 2410 may be performed by a RTT manager as described withreference to FIGS. 10 through 13.

At 2415, the UE may determine a range of timing advance values based onthe scheduling offset, where the timing advance is determined based onthe range. The operations of 2415 may be performed according to themethods described herein. In some examples, aspects of the operations of2415 may be performed by a TA manager as described with reference toFIGS. 10 through 13.

At 2420, the UE may determine a timing advance based on the schedulingoffset and the round trip time. The operations of 2420 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2420 may be performed by a TA manager as describedwith reference to FIGS. 10 through 13.

At 2425, the UE may transmit an uplink message to the base station basedon the timing advance. The operations of 2425 may be performed accordingto the methods described herein. In some examples, aspects of theoperations of 2425 may be performed by an uplink manager as describedwith reference to FIGS. 10 through 13.

FIG. 25 shows a flowchart illustrating a method 2500 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 2500 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 2500 may beperformed by a communications manager as described with reference toFIGS. 10 through 13. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 2505, the UE may receive, from a base station, an indication of ascheduling offset between a downlink radio frame timing structure and anuplink radio frame timing structure. The operations of 2505 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2505 may be performed by a schedulingoffset manager as described with reference to FIGS. 10 through 13.

At 2510, the UE may determine a round trip time for communications withthe base station. The operations of 2510 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 2510 may be performed by a RTT manager as described withreference to FIGS. 10 through 13.

At 2515, the UE may receive an indication of a common offset associatedwith a cell served by the base station, where the timing advance isdetermined based on the common offset. The operations of 2515 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2515 may be performed by a common offsetmanager as described with reference to FIGS. 10 through 13.

At 2520, the UE may determine a network offset between a networkdownlink radio frame timing structure and a network uplink radio frametiming structure, where the timing advance is determined based on thenetwork offset. The operations of 2520 may be performed according to themethods described herein. In some examples, aspects of the operations of2520 may be performed by a network offset manager as described withreference to FIGS. 10 through 13.

At 2525, the UE may determine a range of timing advance values based onthe scheduling offset, the common offset, network offset, or somecombination thereof. For example, the UE may determine a range of timingadvance values based on a delta value, an upper timing advance limit, atiming advance threshold, etc. in accordance with the techniquesdescribed herein (e.g., which may be specified or configured by thenetwork). The operations of 2525 may be performed according to themethods described herein. In some examples, aspects of the operations of2525 may be performed by a TA manager as described with reference toFIGS. 10 through 13.

At 2530, the UE may determine a timing advance based on the range. Forexample, the UE may determine a timing advance based on the schedulingoffset and the determined round trip time (e.g., while adhering to therange determined at 2525). The operations of 2530 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2530 may be performed by a TA manager as describedwith reference to FIGS. 10 through 13.

At 2535, the UE may transmit an uplink message to the base station basedon the timing advance. The operations of 2535 may be performed accordingto the methods described herein. In some examples, aspects of theoperations of 2535 may be performed by an uplink manager as describedwith reference to FIGS. 10 through 13.

FIG. 26 shows a flowchart illustrating a method 2600 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 2600 may be implemented by a base station 105 or its componentsas described herein. For example, the operations of method 2600 may beperformed by a communications manager as described with reference toFIGS. 14 through 17. In some examples, a base station may execute a setof instructions to control the functional elements of the base stationto perform the functions described below. Additionally or alternatively,a base station may perform aspects of the functions described belowusing special-purpose hardware.

At 2605, the base station may determine a minimum round trip time forcommunications with a UE. The operations of 2605 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2605 may be performed by a RTT manager as describedwith reference to FIGS. 14 through 17.

At 2610, the base station may transmit, to the UE, an indication of ascheduling offset between a downlink radio frame timing structure and anuplink radio frame timing structure. The operations of 2610 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2610 may be performed by a schedulingoffset manager as described with reference to FIGS. 14 through 17.

At 2615, the base station may receive an uplink message from the UEbased on the scheduling offset. The operations of 2615 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2615 may be performed by an uplink manager asdescribed with reference to FIGS. 14 through 17.

FIG. 27 shows a flowchart illustrating a method 2700 that supportstiming improvements for wireless communications systems in accordancewith one or more aspects of the present disclosure. The operations ofmethod 2700 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 2700 may beperformed by a communications manager as described with reference toFIGS. 10 through 13. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 2705, the UE may receive, from a base station, a random accessresponse message including a fractional timing advance. The operationsof 2705 may be performed according to the methods described herein. Insome examples, aspects of the operations of 2705 may be performed by aRACH manager as described with reference to FIGS. 10 through 13.

At 2710, the UE may determine a differential offset between a first slotboundary associated with a base station radio frame timing structure anda second slot boundary associated with a UE radio frame timingstructure. The operations of 2710 may be performed according to themethods described herein. In some examples, aspects of the operations of2710 may be performed by a differential offset manager as described withreference to FIGS. 10 through 13.

At 2715, the UE may transmit, to the base station in response to therandom access response message, a second random access message includingthe differential offset. The operations of 2715 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2715 may be performed by a RACH manager as describedwith reference to FIGS. 10 through 13.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may bedescribed for purposes of example, and LTE, LTE-A, LTE-A Pro, or NRterminology may be used in much of the description, the techniquesdescribed herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NRnetworks. For example, the described techniques may be applicable tovarious other wireless communications systems such as Ultra MobileBroadband (UMB), Institute of Electrical and Electronics Engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, aswell as other systems and radio technologies not explicitly mentionedherein.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connectionwith the disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, a CPU, an FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyprocessor, controller, microcontroller, or state machine. A processormay also be implemented as a combination of computing devices (e.g., acombination of a DSP and a microprocessor, multiple microprocessors, oneor more microprocessors in conjunction with a DSP core, or any othersuch configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein may be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that may beaccessed by a general-purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude RAM, ROM, electrically erasable programmable ROM (EEPROM), flashmemory, compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that may be used to carry or store desired programcode means in the form of instructions or data structures and that maybe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio, and microwave areincluded in the definition of computer-readable medium. Disk and disc,as used herein, include CD, laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an example step that is described as “based on condition A”may be based on both a condition A and a condition B without departingfrom the scope of the present disclosure. In other words, as usedherein, the phrase “based on” shall be construed in the same manner asthe phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “example” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, known structures and devices are shown inblock diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person having ordinaryskill in the art to make or use the disclosure. Various modifications tothe disclosure will be apparent to a person having ordinary skill in theart, and the generic principles defined herein may be applied to othervariations without departing from the scope of the disclosure. Thus, thedisclosure is not limited to the examples and designs described herein,but is to be accorded the broadest scope consistent with the principlesand novel features disclosed herein.

The following provides an overview of aspects of the present disclosure:

Aspect 1: A method for wireless communication, comprising: receiving,from a base station, an indication of a scheduling offset between adownlink radio frame timing structure and an uplink radio frame timingstructure, and transmitting an uplink message to the base station basedon a timing advance, the timing advance based at least in part on thereceived indication of the scheduling offset.

Aspect 2: The method of aspect 1, further comprising: determining arange of timing advance values based on the scheduling offset, where thetiming advance may be determined based on the range.

Aspect 3: The method of any one of aspects 1 through 2, furthercomprising: determining an orbit type associated with the base station,wherein the range is determined based at least in part on the orbittype.

Aspect 4: The method of any one of aspects 1 through 3, furthercomprising: determining a timing advance threshold, wherein the timingadvance is determined based at least in part on the timing advancethreshold.

Aspect 5: The method of any one of aspects 1 through 4, wherein thetiming advance threshold is determined based at least in part on one ormore of a slot duration, a radio frame numerology, and a bufferingcapability of the UE.

Aspect 6: The method of any one of aspects 1 through 5, furthercomprising: receiving an indication of a common offset associated with acell served by the base station, wherein the timing advance isdetermined based at least in part on the common offset.

Aspect 7: The method of any one of aspects 1 through 6, furthercomprising: determining a range of timing advance values based at leastin part on the common offset, wherein the timing advance is determinedbased at least in part on the range.

Aspect 8: The method of any one of aspects 1 through 7, wherein thetiming advance is based at least in part on a round trip time forcommunications with the base station.

Aspect 9: The method of aspect 8, wherein the round trip time forcommunications with the base station is determined based at least inpart on one or more of a position of the UE, a position of the basestation, a distance between the UE and the base station, a timestampcorresponding to a downlink message received from the base station, anda local timestamp.

Aspect 10: The method of any one of aspects 1 through 9, furthercomprising: determining a network offset between a network downlinkradio frame timing structure and a network uplink radio frame timingstructure, wherein the timing advance is determined based at least inpart on the network offset.

Aspect 11: The method of any one of aspects 1 through 10, furthercomprising: determining a range of timing advance values based at leastin part on the network offset, wherein the timing advance is determinedbased at least in part on the range

Aspect 12: The method of any one of aspects 1 through 11, furthercomprising: receiving an indication of the network offset, wherein thenetwork offset is determined based on the indication of the networkoffset

Aspect 13: The method of any one of aspects 1 through 12, furthercomprising: determining a minimum offset between the downlink radioframe timing structure and the uplink radio frame timing structure,wherein the timing advance is determined based at least in part on theminimum offset

Aspect 14: The method of any one of aspects 1 through 13, furthercomprising: determining an initial timing advance based at least in parton the minimum offset and transmitting a physical random access channelmessage based at least in part on the initial timing advance.

Aspect 15: The method of any one of aspects 1 through 14, wherein thescheduling offset is based at least in part on a non-terrestrialnetwork.

Aspect 16: An apparatus for wireless communications comprising at leastone means for performing a method of any one of aspects 1 through 15.

Aspect 17: An apparatus for wireless communication comprising aprocessor, and memory coupled to the processor, the processor and memoryconfigured to perform a method of any one of aspects 1 through 15.

Aspect 18: A non-transitory computer-readable medium storing code forwireless communication comprising a processor, memory in electroniccommunication with the processor, and instructions stored in the memoryand executable by the processor to cause the apparatus to perform amethod of any one of aspects 1 through 15.

Aspect 19: A method for wireless communication, comprising:transmitting, to the UE, an indication of a scheduling offset between adownlink radio frame timing structure and an uplink radio frame timingstructure, and receiving an uplink message from the UE based at least inpart on a range of timing advance values, the range of timing advancevalues based at least in part on the scheduling offset.

Aspect 20: The method of aspect 19, further comprising: determining therange of timing advance values based at least in part on the schedulingoffset, wherein the uplink message is received from the UE based atleast in part on the range.

Aspect 21: The method of any one of aspects 19 through 20, furthercomprising: determining an orbit type associated with the base station,wherein the range is determined based at least in part on the orbittype.

Aspect 22: The method of any one of aspects 19 through 21, furthercomprising: determining a timing advance threshold, wherein a timingadvance is determined based at least in part on the timing advancethreshold.

Aspect 23: The method of any one of aspects 19 through 22, wherein thetiming advance threshold is determined based at least in part on one ormore of a slot duration, a radio frame numerology, and a bufferingcapability of the UE

Aspect 24: The method of any one of aspects 19 through 23, furthercomprising: determining a common offset associated with a cell served bythe base station and transmitting an indication of the common offset tothe UE, wherein the uplink message is received from the UE based atleast in part on the common offset.

Aspect 25: The method of any one of aspects 19 through 24, furthercomprising: determining a network offset between a network downlinkradio frame timing structure and a network uplink radio frame timingstructure, wherein the uplink message is received from the UE based atleast in part on the network offset.

Aspect 26: The method of any one of aspects 19 through 25, furthercomprising: transmitting an indication of the network offset to the UE.

Aspect 27: The method of any one of aspects 19 through 26, furthercomprising: determining a minimum offset between the downlink radioframe timing structure and the uplink radio frame timing structure,wherein a timing advance is determined based at least in part on theminimum offset.

Aspect 28: The method of any one of aspects 19 through 27, furthercomprising: determining an initial timing advance based at least in parton the minimum offset and receiving a physical random access channelmessage from the UE based at least in part on the initial timingadvance.

Aspect 29: The method of any one of aspects 19 through 28, wherein thescheduling offset is based at least in part on a non-terrestrialnetwork.

Aspect 30: An apparatus for wireless communications comprising at leastone means for performing a method of any one of aspects 19 through 29.

Aspect 31: An apparatus for wireless communication comprising aprocessor, and memory coupled to the processor, the processor and memoryconfigured to perform a method of any one of aspects 19 through 29.

Aspect 32: A non-transitory computer-readable medium storing code forwireless communication comprising a processor, memory in electroniccommunication with the processor, and instructions stored in the memoryand executable by the processor to cause the apparatus to perform amethod of any one of aspects 19 through 29.

Aspect 33: A method for wireless communication, comprising: receiving,from a base station, a random access response message comprising afractional timing advance, and transmitting, to the base station inresponse to the random access response message, a second random accessmessage comprising a differential offset between a first slot boundaryassociated with a base station radio frame timing structure and a secondslot boundary associated with a UE radio frame timing structure.

Aspect 34: The method of aspect 33, further comprising: determining around trip time for communications with a base station, transmitting afirst random access message to the base station based at least in parton the round trip time, wherein the random access response message isreceived based at least in part on transmitting the first random accessmessage.

Aspect 35: The method of any one of aspects 33 through 34, furthercomprising: determining a scrambling sequence, a hopping pattern, orboth based at least in part on the round trip time.

Aspect 36: The method of any one of aspects 33 through 35, furthercomprising: determining a timing advance based at least in part on thedifferential offset, and transmitting an uplink message to the basestation based at least in part on the timing advance.

Aspect 37: The method of any one of aspects 33 through 36, furthercomprising: receiving, from the base station, an indication to shift theUE radio frame timing structure, and shifting the UE radio frame timingstructure based at least in part on the indication, wherein the timingadvance is determined based at least in part on the shifting

Aspect 38: The method of any one of aspects 33 through 37, wherein thedifferential offset is determined based at least in part on thefractional timing advance.

Aspect 39: The method of any one of aspects 33 through 38, wherein thebase station is associated with a non-terrestrial network.

Aspect 40: An apparatus for wireless communications comprising at leastone means for performing a method of any one of aspects 33 through 39.

Aspect 41: An apparatus for wireless communication comprising aprocessor, and memory coupled to the processor, the processor and memoryconfigured to perform a method of any one of aspects 33 through 39.

Aspect 42: A non-transitory computer-readable medium storing code forwireless communication comprising a processor, memory in electroniccommunication with the processor, and instructions stored in the memoryand executable by the processor to cause the apparatus to perform amethod of any one of aspects 33 through 39.

Aspect 43: A method for wireless communication, comprising: receiving,from a base station, an indication of a scheduling offset between adownlink radio frame timing structure and an uplink radio frame timingstructure, determining a round trip time for communications with thebase station, determining a timing advance based on the schedulingoffset and the round trip time, and transmitting an uplink message tothe base station based on the timing advance.

Aspect 44: The method of aspect 43, further comprising: determining arange of timing advance values based on the scheduling offset, where thetiming advance may be determined based on the range.

Aspect 45: The method of any one of aspects 43 through 44, furthercomprising: determining an orbit type associated with the base station,wherein the range is determined based at least in part on the orbittype.

Aspect 46: The method of any one of aspects 43 through 45, furthercomprising: determining a timing advance threshold, wherein the timingadvance is determined based at least in part on the timing advancethreshold.

Aspect 47: The method of any one of aspects 43 through 46, wherein thetiming advance threshold is determined based at least in part on one ormore of a slot duration, a radio frame numerology, and a bufferingcapability of the UE.

Aspect 48: The method of any one of aspects 43 through 47, furthercomprising: receiving an indication of a common offset associated with acell served by the base station, wherein the timing advance isdetermined based at least in part on the common offset.

Aspect 49: The method of any one of aspects 43 through 48, furthercomprising: determining a range of timing advance values based at leastin part on the common offset, wherein the timing advance is determinedbased at least in part on the range.

Aspect 50: The method of any one of aspects 43 through 49, wherein theround trip time for communications with the base station is determinedbased at least in part on one or more of a position of the UE, aposition of the base station, a distance between the UE and the basestation, a timestamp corresponding to a downlink message received fromthe base station, and a local timestamp.

Aspect 51: The method of any one of aspects 43 through 50, furthercomprising: determining a network offset between a network downlinkradio frame timing structure and a network uplink radio frame timingstructure, wherein the timing advance is determined based at least inpart on the network offset.

Aspect 52: The method of any one of aspects 43 through 51, furthercomprising: determining a range of timing advance values based at leastin part on the network offset, wherein the timing advance is determinedbased at least in part on the range

Aspect 53: The method of any one of aspects 43 through 52, furthercomprising: receiving an indication of the network offset, wherein thenetwork offset is determined based on the indication of the networkoffset

Aspect 54: The method of any one of aspects 43 through 53, furthercomprising: determining a minimum offset between the downlink radioframe timing structure and the uplink radio frame timing structure,wherein the timing advance is determined based at least in part on theminimum offset

Aspect 55: The method of any one of aspects 43 through 54, furthercomprising: determining an initial timing advance based at least in parton the minimum offset and transmitting a physical random access channelmessage based at least in part on the initial timing advance.

Aspect 56: The method of any one of aspects 43 through 55, wherein thescheduling offset is based at least in part on a non-terrestrialnetwork.

Aspect 57: An apparatus for wireless communications comprising at leastone means for performing a method of any one of aspects 43 through 56.

Aspect 58: An apparatus for wireless communication comprising aprocessor, memory in electronic communication with the processor, andinstructions stored in the memory and executable by the processor tocause the apparatus to perform a method of any one of aspects 43 through56.

Aspect 59: A non-transitory computer-readable medium storing code forwireless communication comprising a processor, memory in electroniccommunication with the processor, and instructions stored in the memoryand executable by the processor to cause the apparatus to perform amethod of any one of aspects 43 through 56.

Aspect 60: A method for wireless communication, comprising: determininga minimum round trip time for communications with a UE, transmitting, tothe UE, an indication of a scheduling offset between a downlink radioframe timing structure and an uplink radio frame timing structure, andreceiving an uplink message from the UE based at least in part on thescheduling offset.

Aspect 61: The method of aspect 60, further comprising: determining arange of timing advance values based at least in part on the schedulingoffset, wherein the uplink message is received from the UE based atleast in part on the range.

Aspect 62: The method of any one of aspects 60 through 61, furthercomprising: determining an orbit type associated with the base station,wherein the range is determined based at least in part on the orbittype.

Aspect 63: The method of any one of aspects 60 through 62, furthercomprising: determining a timing advance threshold, wherein the timingadvance is determined based at least in part on the timing advancethreshold.

Aspect 64: The method of any one of aspects 60 through 63, wherein thetiming advance threshold is determined based at least in part on one ormore of a slot duration, a radio frame numerology, and a bufferingcapability of the UE

Aspect 65: The method of any one of aspects 60 through 64, furthercomprising: determining a common offset associated with a cell served bythe base station and transmitting an indication of the common offset tothe UE, wherein the uplink message is received from the UE based atleast in part on the common offset.

Aspect 66: The method of any one of aspects 60 through 65, furthercomprising: determining a network offset between a network downlinkradio frame timing structure and a network uplink radio frame timingstructure, wherein the uplink message is received from the UE based atleast in part on the network offset.

Aspect 67: The method of any one of aspects 60 through 66, furthercomprising: transmitting an indication of the network offset to the UE.

Aspect 68: The method of any one of aspects 60 through 67, furthercomprising: determining a minimum offset between the downlink radioframe timing structure and the uplink radio frame timing structure,wherein the timing advance is determined based at least in part on theminimum offset.

Aspect 69: The method of any one of aspects 60 through 68, furthercomprising: determining an initial timing advance based at least in parton the minimum offset and receiving a physical random access channelmessage from the UE based at least in part on the initial timingadvance.

Aspect 70: The method of any one of aspects 60 through 69, wherein thescheduling offset is based at least in part on a non-terrestrialnetwork.

Aspect 71: An apparatus for wireless communications comprising at leastone means for performing a method of any one of aspects 60 through 70.

Aspect 72: An apparatus for wireless communication comprising aprocessor, memory in electronic communication with the processor, andinstructions stored in the memory and executable by the processor tocause the apparatus to perform a method of any one of aspects 60 through70.

Aspect 73: A non-transitory computer-readable medium storing code forwireless communication comprising a processor, memory in electroniccommunication with the processor, and instructions stored in the memoryand executable by the processor to cause the apparatus to perform amethod of any one of aspects 60 through 70.

Aspect 74: A method for wireless communication, comprising: receiving,from a base station, a random access response message comprising afractional timing advance, determining, a differential offset between afirst slot boundary associated with a base station radio frame timingstructure and a second slot boundary associated with a UE radio frametiming structure, and transmitting, to the base station in response tothe random access response message, a second random access messagecomprising the differential offset.

Aspect 75: The method of aspect 74, further comprising: determining around trip time for communications with a base station, transmitting afirst random access message to the base station based at least in parton the round trip time, wherein the random access response message isreceived based at least in part on transmitting the first random accessmessage.

Aspect 76: The method of any one of aspects 74 through 75, furthercomprising: determining a scrambling sequence, a hopping pattern, orboth based at least in part on the round trip time.

Aspect 77: The method of any one of aspects 74 through 76, furthercomprising: determining a timing advance based at least in part on thedifferential offset, and transmitting an uplink message to the basestation based at least in part on the timing advance.

Aspect 78: The method of any one of aspects 74 through 77, furthercomprising: receiving, from the base station, an indication to shift theUE radio frame timing structure, and shifting the UE radio frame timingstructure based at least in part on the indication, wherein the timingadvance is determined based at least in part on the shifting

Aspect 79: The method of any one of aspects 74 through 78, wherein thedifferential offset is determined based at least in part on thefractional timing advance.

Aspect 80: The method of any one of aspects 74 through 79, wherein thebase station is associated with a non-terrestrial network.

Aspect 81: An apparatus for wireless communications comprising at leastone means for performing a method of any one of aspects 74 through 80.

Aspect 82: An apparatus for wireless communication comprising aprocessor, memory in electronic communication with the processor, andinstructions stored in the memory and executable by the processor tocause the apparatus to perform a method of any one of aspects 74 through80.

Aspect 83: A non-transitory computer-readable medium storing code forwireless communication comprising a processor, memory in electroniccommunication with the processor, and instructions stored in the memoryand executable by the processor to cause the apparatus to perform amethod of any one of aspects 74 through 80.

What is claimed is:
 1. A method for wireless communication at a user equipment (UE), comprising: receiving, from a base station, an indication of a scheduling offset between a downlink radio frame timing structure and an uplink radio frame timing structure; and transmitting an uplink message to the base station based at least in part on a timing advance, the timing advance based at least in part on the received indication of the scheduling offset.
 2. The method of claim 1, further comprising: determining a range of timing advance values based at least in part on the scheduling offset, wherein the timing advance is determined based at least in part on the range.
 3. The method of claim 2, further comprising: determining an orbit type associated with the base station, wherein the range is determined based at least in part on the orbit type.
 4. The method of claim 1, further comprising: determining a timing advance threshold, wherein the timing advance is determined based at least in part on the timing advance threshold.
 5. The method of claim 4, wherein the timing advance threshold is determined based at least in part on one or more of a slot duration, a radio frame numerology, and a buffering capability of the UE.
 6. The method of claim 1, further comprising: receiving an indication of a common offset associated with a cell served by the base station, wherein the timing advance is determined based at least in part on the common offset.
 7. The method of claim 6, further comprising: determining a range of timing advance values based at least in part on the common offset, wherein the timing advance is determined based at least in part on the range.
 8. The method of claim 1, wherein the timing advance is based at least in part on a round trip time for communications with the base station.
 9. The method of claim 8, wherein the round trip time for communications with the base station is determined based at least in part on one or more of a position of the UE, a position of the base station, a distance between the UE and the base station, a timestamp corresponding to a downlink message received from the base station, and a local timestamp.
 10. The method of claim 1, further comprising: determining a network offset between a network downlink radio frame timing structure and a network uplink radio frame timing structure, wherein the timing advance is determined based at least in part on the network offset.
 11. The method of claim 10, further comprising: determining a range of timing advance values based at least in part on the network offset, wherein the timing advance is determined based at least in part on the range.
 12. The method of claim 10, further comprising: receiving an indication of the network offset, wherein the network offset is determined based on the indication of the network offset.
 13. The method of claim 10, further comprising: determining a minimum offset between the downlink radio frame timing structure and the uplink radio frame timing structure, wherein the timing advance is determined based at least in part on the minimum offset.
 14. The method of claim 13, further comprising: determining an initial timing advance based at least in part on the minimum offset; and transmitting a physical random access channel message based at least in part on the initial timing advance.
 15. The method of claim 1, wherein the scheduling offset is based at least in part on a non-terrestrial network.
 16. A method for wireless communication at a user equipment (UE), comprising: receiving, from a base station, a random access response message comprising a fractional timing advance; and transmitting, to the base station in response to the random access response message, a second random access message comprising a differential offset between a first slot boundary associated with a base station radio frame timing structure and a second slot boundary associated with a UE radio frame timing structure.
 17. The method of claim 16, further comprising: determining a round trip time for communications with a base station; and transmitting a first random access message to the base station based at least in part on the round trip time, wherein the random access response message is received based at least in part on transmitting the first random access message.
 18. The method of claim 17, further comprising: determining a scrambling sequence, a hopping pattern, or both based at least in part on the round trip time.
 19. The method of claim 16, further comprising: determining a timing advance based at least in part on the differential offset; and transmitting an uplink message to the base station based at least in part on the timing advance.
 20. The method of claim 19, further comprising: receiving, from the base station, an indication to shift the UE radio frame timing structure; and shifting the UE radio frame timing structure based at least in part on the indication, wherein the timing advance is determined based at least in part on the shifting.
 21. The method of claim 16, wherein the differential offset is determined based at least in part on the fractional timing advance.
 22. The method of claim 16, wherein the base station is associated with a non-terrestrial network.
 23. A method for wireless communication at a base station, comprising: transmitting, to the UE, an indication of a scheduling offset between a downlink radio frame timing structure and an uplink radio frame timing structure; and receiving an uplink message from the UE based at least in part on a range of timing advance values, the range of timing advance values based at least in part on the scheduling offset.
 24. The method of claim 23, further comprising: determining the range of timing advance values based at least in part on the scheduling offset, wherein the uplink message is received from the UE based at least in part on the range.
 25. The method of claim 24, further comprising: determining an orbit type associated with the base station, wherein the range is determined based at least in part on the orbit type.
 26. The method of claim 23, further comprising: determining a timing advance threshold, wherein a timing advance is determined based at least in part on the timing advance threshold.
 27. The method of claim 23, further comprising: determining a common offset associated with a cell served by the base station; and transmitting an indication of the common offset to the UE, wherein the uplink message is received from the UE based at least in part on the common offset.
 28. The method of claim 23, further comprising: determining a network offset between a network downlink radio frame timing structure and a network uplink radio frame timing structure, wherein the uplink message is received from the UE based at least in part on the network offset; and transmitting an indication of the network offset to the UE.
 29. The method of claim 28, further comprising: determining a minimum offset between the downlink radio frame timing structure and the uplink radio frame timing structure, wherein a timing advance is determined based at least in part on the minimum offset.
 30. An apparatus for wireless communication at a user equipment (UE), comprising: a processor; and memory coupled to the processor, the processor and memory configured to: receive, from a base station, an indication of a scheduling offset between a downlink radio frame timing structure and an uplink radio frame timing structure; and transmit an uplink message to the base station based at least in part on a timing advance, the timing advance based at least in part on the received indication of the scheduling offset. 